One other factor I didn’t mention is that some lasers have optical feedback from photodiodes. This could have been the case as well here that is causing some dimming.
As a former fiber optic tech, it'd be cool to see a similar video to this, but implenting use of an OTDR (Optical Time-Domain Reflectometer) it's a digital device which acts as its name would imply* also acts as a laser light power meter - usually just called a power meter, in-context - (make and model dependent), as well as an integrated light source(make and model dependent) *In simplest terms, an OTDR measures the number of internal reflections over a given length of optical fiber over the course of a set amount of time, in order to determine things like overall length of a fiber(sometimes an entire run if it's of suitable distance for the specs and calibration of the OTDR), presence, approximate degree, and location of damage, and more. There's a lot of really interesting experimentation that could be done with one, in the hands of a creative intellect. I'd like to say i had a chance to, but playing around with equipment that's usually active, and whose activity means carrying extremely important and oftentimes expensive data EXTREMELY QUICKLY, between sometimes very distant and/or potentially *_objectively_* important places, all the while, said data(as laser light) is being not only propagated/produced, but also repeated, amplified, stored, and interpreted on and by equipment which is *_also_* *_EXTREMELY EXPENSIVE_* - as a person with clear ethics, an average-ish budget, and *_NO_* desire whatsoever to spend time in prison, I wouldn't dare. Not on my worst day.😂 But experimenting with inactive equipment. Now that i can get behind. Only problem is that *_decent_* - and that distinction *_is_* important - OTDRs themselves *_tend to be_* *_prohibitively_* expensive. Less-so used, but still so. particularly for anyone who isn't an ISP or fiber optic installer/testing, maintenance & repair company. In any case, I wonder what effect there'd be by applying the blackest black or whitest white to optical fiber. Either along the jacket of the cable (Some light escapes the fibers and cables even though we can't usually see it, if you can, there's problems, or its just bent too far and there *_soon shall be_* problems), or *_gently_* around *_just_* the wall of the ferrule(glass tip; fiber itself is also glass, *_each_* the approximate diameter of *_a_* human hair.) - and/or maybe even inside the connector. Would it negate/absorb too much light? Or would it help the light better direct itself? Or using optical equipment in the blackest room, whitest room, or even an internally mirrored box. Would it even affect the readings at all? 🤔 Would also be a very good opportunity to potentially (probably long-distance) collab with Brainiac75, one of my other longtime favorites on this platform. He also rather enjoys lasers and a number of other interesting aspects of science and gadgetry. 😁
Shouldn't there also be constructive interference sometimes in addition to destructive interference when you move the lase away from the mirror a bit? It should get brighter at some distances.
@@ConfidentialMeerkat you know it just recently struck me that I don't think I've ever seen a collab between him and any of the other big science/engineering channels...it never occurred to me how odd it was until this sketchy behavior surfaced. Now I'm wondering if these things are related
I thought people were exaggerating about how you handled critical feedback and I gave you the benefit of the doubt but after seeing how many comments were just purged I've lost a lot of respect. Many of which were still trying to be respectful while pointing out their concerns about a certain company. This isn't a good look man. It isn't just about negativity.
@@ConfidentialMeerkat With that attitude, you prolly was shadowbanned from the site itself for spamming comments thinking it would change something, although I can see and reply to you...
got the notification that you replied to my comment where i explained the situation, so i went to read it and what’d ya know, the original comment is deleted/hidden now.
@@ConfidentialMeerkat I have this issue with the channel Wham Bam Tesla Cam, they auto-block any comment I make correcting them when they say "instant justice" and I tell them it's instant karma. Weird how may channels have auto-banning features like that.
@@biglewis7 I guarantee you've had "shadowed" comments you didn't know about. It happens on benign comments all the time that are just worded in some way the black box doesn't like. It does a better job removing harmless replies than the obvious bots we see every day.
I heard the name of that company way too many times on this chanel, even though hundreds of people, including myself, made bad comments about it in the past. I'm out.
who cares about morals and ruined lives by awful therapist working on people on brink of suicide, when you can make a bank... completely shameless, but yeah sure have my comment to boost your algo
@@ConfidentialMeerkatyeah, I was actually considering using BH a year or so ago until I discovered that little factoid. That's such a depraved move, selling people's secrets to advertisers so they can more easily manipulate people in an unstable emotional state...
Nope. I had gotten the gist of what he was repeating himself saying and was scrolling through comments just about still listening by that point. Only went back and replayed that time stamp to work out what you were on about
@@Scarabaeus15 We are still talking about the hair, right? (nah, I'm joking) At least we can be sure that each removed comment has been read first and they're aware of us being aware.
But for optimal efficiency use a 5k milliwatt or 5 watt 445 nm diode. Actually never do this . I'm joking as a matter of fact don't even look at the splash in the wall without appropriate goggles,it is equivalent to watching someone weld
@@HankyPankythedog As you said, don't do it with any lasers. But especially don't do it with blue ones. Technical stuff - blue light is created from UV light, which is invisible to a human eye. You can blind yourself or other person not even knowing you pointed that thing if it's damaged. [edit] Ok, forgot about green lasers - the thing I was talking about was shown at the end with a green and blue laser. That's what happens when you write comments half way through the clip 😁
Interesting video. Laser diodes are pretty much always fed with a control loop that samples some of their output. Without the control loop they would burn themselves out. Part of what you are seeing might have to due with this control loop, rather than destructive interference.
That's a good point. The somewhat more expensive laser pointers have OPC. If the reflected beam hits the sense-diode, the control loop will actively reduce the laser current. The cheapo models don't have this they are simply current limiters.
There are several ways to control the Laser Diodes, the simplest is just current control, which is simple (might be just a resistor) and gives reasonable results, but you do get a moderate intensity variation over temperature. Optical feedback allows more constant intensity output. A cheap pointer might just use the current control and set the current low enough to never get above the allowed limits over temperature (or just ignore the rules ;) ), a better one would use the feedback, and that WILL greatly drop in intensity from the returned signal.
Not going to pretend to know what you're fully talking about, but I have to agree the chances of it being destructive interferance seems insanely small. Being able to cause destructive interference purely by hand would be effectievly impossible.
Are you sure it's the destructive interference? When you're perfectly in line, fewer observable photons escape, so the light appears dimmer. There MAY be destructive interference, but you only addressed that in theory, not in demonstration.
You can delete specific comments, but you can't stop us from leaving. Don't support the group with the green logo mentioned around 2 minutes into this video
Totally agree with you. They employ people who have NO IDEA how to do the_apy. The the_apist told me to "stop being a bad person" when I wanted to work on my borderline personality dissorder. That is beyond insanity. It lead me to the point of being suicidaI. They also charged me for that. they were also caught selling "medicaI records" to third parties.
"I'm not moving it at all, but it's flickering" As long as you are alive, you are always moving at least a little bit -- whether intentionally or inadvertently
I was thinking the same thing. Whether thorough the blood pumping through the fingers or muscles and tendons stretching and what not, the laser beam would be constantly moving and changing angle. Still, he was able to keep it steady enough and close enough to observe an interaction.
@@coreyduggan1246 yeah but he made it seem like the flickering was part of the effect rather than him definitely causing it. Perfect alignment should result in a circular interference pattern and no flickering
3:25 Fun fact: this probably only works with un-angled "UPC" connectors, like the one shown in the video, indicated by the blue connector housing. There are also the much more common green APC connectors, which are angled at an 8° angle to reduce the amount of light reflected back into the fibre, making for a better connection.
They're not more common in the industry in general, but you see them ubiquitously in GPON installations because otherwise the reflected light interferes with the passive splitting system, you also see them on anything with a high power laser so that it doesn't burn itself out, or destroy the laser amplifier. Your average GPON also has a nice chunky laser on the head end because it's split down so many times, so they're just used everywhere on the system.
5:42 the reflected light isn't non-coherent with the laser output light, it's actually pretty much in anti-phase. Interference can only happen between waves that are coherent to one another. The mirror doesn't jumble the phase randomly, it flips it about 180°. If you shone a different laser into your laser, the two would be incoherent between themselves, and the effect would be pretty minimal, maybe even non existent.
It collimates further on reflection into itself, so it isn't necessarily dimmer, we just see less rays, just like you can't see laser light in the air, unless there are particles in the air to diffuse it.
In audio engineering when you reverse the phase of an audio waveform and lay it directly over the un-inverted wave, you get phase cancellation. you'd think you'd get twice as much volume but you don't. In otherwords, you don't hear the audio at all. Could this be the same in this case? Waves of sound, wav e of light. Same right? Is the mirror inverting the wave of light?
That sounds pretty much correct. If you have a wave that is out of phase by any significant amount it will interfere. Beat patterns when tuning a guitar for example as you get them closer in tune you'll hear the interference as a rapid modulation in volume that will occur slower and slower all the way until it's perfectly in tune. If the wave is antiphase it will cancel perfectly and no power will be transmitted.
Dropping out. Yet again you use that company while it's *dangerous* to it's customers, it's consistently so, and you know it by now. You are willfully causing harm to your viewers.
@rubrtt absolutely nothing. What you're seeing is just a bunch of self-righteous losers pretending there's a crusade to be had because they're bored and have nothing better to do. Absolutely nobody who claims there's an issue with the company has any real evidence to support their claims. It's all anecdotal "evidence" referencing the *one* time someone had a (what *seems* to be) legitimate complaint about a lack of credentials preceeding a single incident.
Try the same trick with a helium-neon gas laser tube. Beam will get much, much brighter when you line up the mirror correctly (front surface only!) It's a very sensitive adjustment...we had to use clamps and the like to make it work.
You should try another types of lasers. Diode lasers have optical feedback very often. A built in photodiode to control optical power of laser. So flickering is feedback work.
PLEASE for the love of god use a different paid section. There are better options that don’t violate your privacy. It’s getting ridiculous at this point, it’s not like you don’t know what they’ve done and instead having yt delete comments.
I had the opportunity to talk with Art Schawlow, Nobel winning physicist back in the early 80s in Palo Alto. He carried a hand held laser with him for demonstrations when lasers were new. Great man with child like curiosity.
Some types of red laser diodes contain an internal monitor photodiode (on which some of the emitted light goes), to allow feedback on the optical output power. Presumably, the laser diode emits less power because the returning beam hits the monitor photodiode, causing a reduction in the drive current of the laser diode 😊
@@TheActionLab it likely is, I tried this about a decade and change ago with a cheap laser pointer, and rather than dimming, the laser diode just died within seconds when I got the angle perfect to shine back into itself.
try maglev induction coil ore metallic gold silver iron separation from non-magnetic non-conducting sand. maglev induction can also optionally melt the floating stuff.
5:00 Ummm, I think you're overthinking some of this... The laser light is invisible unless it bounces off of something. When you shine it directly back on itself, it's not reflecting off of the frame and PCB, thus appearing to dim the beam. Otherwise 💯🙂
Radio Tower Climber here... With that identical fault indicator flashlight.. it breaks the light up a bunch and it not a focal laser... shine it on the wall you'll see the spiral.. It goes through something that alters the light path so that the laser is shined throughout the entire fiber optic in a way that our testing modules can use to scan the fiber for dirt and fractures more efficiently that a solid light beam.
@@KyryloHryhoriev The Job dons many names.. for instance are you specializing in point to point, repeater/communications, cellular, government specialties like ATAK, or are you the general structural specialist working on the tower itself (paint, lights, maintenance, construction, deconstruction), or are you just a ground guy working ropes and shelters doing all the ground inspections and punch outs. There are some people whose entire job is just driving around with a $20k fiber tester, or RF mapper running tests for companies that either can't afford one, or don't want to rent a unit because it's not a common project use tool. Anyways, I was just pointing out they tried to use a laser in search for a solid beam tool.. I've got that exact light in one of my climb bags and can speak with 100% confidence when I say it's diffused.. If he shines it on the wall he will see the spiral we use to spread the light around in a way that the machines can differential dirt and fractures in the fiber. The climber attaches it at the OVP junction box at the top of the tower (in my use case) and the tester connects at the bottom in the shelter where they insure it wasn't damaged during installation. It's not uncommon for the hybrid cables on a cellular site to cost upwards of $50k, and we brunt a lot of that liability while installing it so we have to cover our asses and document it's condition at the time before and after installation.
4:22 - Um, pretty sure a human can't hold "still" at that infinitesimal scale of particles... your "still" is still a 9+ earthquake on the Richter scale to a photon.
It doesn't have to be at "particle scale", because coherent light is not single particle (although its generated that way). What you should measure against is something called the "coherence length", exactly because coherent light is made of many photons, and is in a certain way macroscopic (not always, but in this case yes). That's why making single photon emitters out of laser light is basically impossible.
@RyanAumiller that's obvious, why point it out? Unless you are autistic and take everything literally? Or pretend to, so that you can try to make others feel stupid? I've been there. I recommend growing out of this phase ASAP.
Actual laser diodes have completely different geometry and construction than shown. No mirrors, optical cavity, emission is perpendicular to the layers, not along the interface. See the Wikipedia article.
You could try to make the feedback less extreme by using an optical grating. The littrow configuration is when you send the first diffraction order back to the grating. Order zero is used as an output. The power goes down well above threshold, but the the threshold reduces. We use this a lot to make very coherent lasers and tunable lasers out of simple laser diodes, they are called ECDL
Simple at home experiment. I used a mirror in my bathroom and put a bit of cigarette smoke in the room. I stood about 8-10 feet away from the mirror and aimed my red laser pointer at the mirror. It took a minute and a steady hand, but I was able to reflect the beam back to the pointer at the aperature. The beam was visible as a dashed line, not solid but with gaps immediately displaying the interference pattern. I was able to do this even without steadying my hand on an object. Really cool looking!
6:25 Hm, so if you wanted it to concentrate the light further, you'd actually want to redesign the laser so that the beam circles back around to the back and fires in at the same direction as the new light being added. Of course, I highly doubt the effectiveness because there's only so much concentration you can get. Entropy and all that.
Great video! I think the dimming effect when reflecting the laser back into itself is due to optical feedback causing mode competition in the laser diode, not destructive interference. Destructive interference would require precise distances and phase alignment, which doesn't seem to be the case here. The back reflection disrupts the laser's operation, leading to reduced power output and instability. This phenomenon is well-known in laser physics, and optical isolators are often used to prevent it.
This sounds very similar to standing waves in audio, where you have areas of dead spot where the waves cancel each other out. Very interesting that it happens to light as well. Thank you
Ok…..thats is the best explanation of how a laser, actually functions to focus a beam of light….Thank you for that. I’ve honestly never heard such a precise and simple explanation. Again….THANK YOU
if i'm correct the light doesn't really cancel itself out into nothing, i know that when two opposing electromagnetic waves collide (let's say p1, p2), the result is either p1+p2 or p1-p2, so the total energy stays the same, and assuming p1=-p2, no light is actually lost, it just doubles half and cancels out half the light. you can see it by the experiment you showed of combining the lazer, it had a corresponding light pattern with the same total energy, some canceled out some amplified. (feel free to correct me, am a silly 17yo currently)
A thought here; does the mirror reverse the wave? If the peaks and troughs are out of phase the intensity will dim. The laser diode will still produce more than is cancelled so you still get some light.
@@michaelwicker9538 He is protecting the company that is selling data of people that arent doing well and before you start saying OTHER COMPANIES ALSO SELL YOUR DATA . Yes other companies do that but THAT COMPANY (My comment will get deleted if I say the name) isnt allowed to do that by FTC because imagine if you went to psychologist and you tell them all your problems but insted of keeping it for themself they will tell to all of petients how would you feel about that
Most lasers, even relatively small lasers, have coatings on exit optics designed to be polarising, this is not only to reduce optical feedback it increases output stability. For high power lasers Faraday isolators are used in the output optics to introduced a 1/4-wave phase shift. Without these features the workpiece / target suffers optical banding as the working distance between the target and the laser generator varies by the wavelength of the system. In high power applications the system is actually designed to be slightly off-axis as well as polarised to introduce yet another safety feature.
The cable length and whether you're using multi mode or single mode transmitter/receiver make a difference. Minimum length is 3 feet if I remember correctly, and that is for multi-mode short range fiber. I don't remember what the minimum for single-mode long range fiber is. I work in IT and I have have had transmitters burn out because the wrong length of cable was used for the type of transmitter.
Fun fact: An older technique for producing ultrashort laser pulsed uses an external cavity and back-reflection into the laser to mode-lock the laser. It's called additive pulse mode-locking.
I will say that when it reflects in itself - we see it dimmer because footons do not reflect to camera lens, but go in. We see only reflection, 90° - no reflection/minimum reflection.
I am glad I am not the only one saying this. If you shine a laser at a piece of paper with a hole in it, it suddenly looks a lot less bright when you shine exactly through the hole.
Exactly with you on this. Chance for observation off axis seems the likely cause it seems darker. It's just not spilling into the environment much for us to observe.
One of the fun experiments I saw in the 90's was putting an argon water cooled lasing into the lesser reflector of a krypton water cooled to make white light. Not very efficient but would still work.
I like watching your videos. Been with the channel when there were around 20K subscribers. You make us understand, even basic things have great concepts and physics involved.
Well this warrants inquiry into more serious questions with heavy ramifications. Should the word L.A.S.E.R. be allowed on the scrabble board if it's officially an acronym? Would changing the spelling such as lasers or lasered constitute keeping it on the board. Do I really have to award Jennifer those 6 points? We pronounce S.C.O.T.U.S. and P.O.T.U.S. as words, but they're not allowed. Would this require a rule change for modern time? No Jennifer, I will not stop typing! I'm letting all these people know your threatening me with a frying pan. If you even think about hhhhhhhhhhhhhhhhhhhhhhhhhhhh. Hey guys! Jen here. Laser stays on the board!
What is happening is cycling through thousands of interference fringes per second. You should try this with recording off the photodiode included with the laser. Also the lower output is also due to the photodiode seeing the reflection, there is a circuit which regulates power output from its feedback photodiode.
I done that before too with lasers. If you don't destroy or warp the mirror of the process it almost seems like it penetrates into some kind of weird mirror dimension.👌
Can you stop sponsoring that company? It sounds like people are leaving because of it… I dont really know anything about this situation, or why people won’t say the name of the company, or what the company even did, but I don’t want you to lose viewers cus u have really great videos :)
This is a very nice demo. It's amazing that you can see these effects with a hand held beam. I am interested in the ability of a feedback laser to increase the coherence length of a blue diode laser. For holography. Special diodes with an anti reflection coating on the output mirror enables the laser to be frequency sharpened in a longer cavity. A high power inexpensive diode system would be a great boon to holography.
Or the laser diode has a monitor photodiode monitoring the output of the laser diode on the other face of the laser chip. By shining light back in the monitor photodiode thinks the laser is outputting more power than it actually is. Hence the drive circuitry turns the current down....
You actually just do not see it as much when it focuses stronger at the tip. I tested that on a sensor years ago. As it gets more focussed it narrows more to the center. It works a little different with each type of laser. It strongly depends on what you are using to create that light with to though.
Actually fun fact, you can measure the light that comes back and use the measurement to calculate the speed and distance of the object the laser is pointing at! I didn't believe this was possible at first, but I made a video on my channel explaining the physics of exactly how it works! It's very cool, there's a few laser sensors out there that use this mechanism!
would it be possible, that you just reflect more light onto the monitor diode, which is part of the feedback loop of the power regulation of the laserdiode? The control loop would then reduce the power, because the monitor diode detects more light than usual.
I tried BH (the sp0ns0r) services. They employ people who have NO IDEA how to do therapy. The therapist told me to "stop being a bad person" when I wanted to work on my borderline personality dissorder. That is beyond insanity. It lead me to the point of being suicidaI. They also charged me for that. they were also caught selling "medical record" to third parties.
The stance of that app was that they are not responsible for checking that the therapist are real therapist or have license "it's responsability of the user to verify that the people is really a licensed professional" they did no return the money of inconforme people, later on they backpedaled some of this but only lip service
Ask Dr Science. When the light flickered and dimmed; did you change places with your reflection in the mirror? Seriously, I really enjoy your content creation. Thank you!
Before you even did this experiment i said it will be out of phase making it go dim. Bingo! Fire it through a tiny hole in a mirror onto another mirror then back through the hole in the mirror. Measure the wavelengths and set your laser to out of phase distance
Even without destructive interference, for example if you happen to match the distance so that there is constructive interference, you are still limited in lasing power by number of lasing centers (atoms). You just can't get more photons than the number of centers that undergo stimulated emission.
Geez... my former laser tech experience makes my spine shivers when you shine laser on that mirror... And touching a mirror surface with fingers? Tsk, tsk. If I did that with a real cutting laser mirror, I would be in trouble 😉 Yes, way back then, when CO2 lasers were a thing, laser techs had to clean and set up mirrors at least once per year. I don't remember now perfectly, but there was a possibility to damage a resonator when cutting highly reflective metals by getting the beam to flash back. I guess if you have a few kW of power in a cutting laser, it looks a bit different then in a pointer. 😁
Diode lasers can be built only from semiconductors that have an exciton state in their band gap. It is only when the exciton density reaches a threshold that the semiconductor amplifies light. Below that threshold, stimulated emission only reduces the attenuation. And amplification evidently is not possible in diodes without excitons. Without excitons you only have a light emitting diode. Reflecting light into a low power laser diode can cause mode hops and even lead to chaotic behavior, but it will not damage them. But, a powerful laser can be damaged if even a small part of the light is reflected back into it.
One other factor I didn’t mention is that some lasers have optical feedback from photodiodes. This could have been the case as well here that is causing some dimming.
That is interesting, I think optical feedback from photodiodes deserves a video of its own. Thanks for the clarification!
As a former fiber optic tech, it'd be cool to see a similar video to this, but implenting use of an OTDR (Optical Time-Domain Reflectometer) it's a digital device which acts as its name would imply* also acts as a laser light power meter - usually just called a power meter, in-context - (make and model dependent), as well as an integrated light source(make and model dependent)
*In simplest terms, an OTDR measures the number of internal reflections over a given length of optical fiber over the course of a set amount of time, in order to determine things like overall length of a fiber(sometimes an entire run if it's of suitable distance for the specs and calibration of the OTDR), presence, approximate degree, and location of damage, and more.
There's a lot of really interesting experimentation that could be done with one, in the hands of a creative intellect. I'd like to say i had a chance to, but playing around with equipment that's usually active, and whose activity means carrying extremely important and oftentimes expensive data EXTREMELY QUICKLY, between sometimes very distant and/or potentially *_objectively_* important places, all the while, said data(as laser light) is being not only propagated/produced, but also repeated, amplified, stored, and interpreted on and by equipment which is *_also_* *_EXTREMELY EXPENSIVE_* - as a person with clear ethics, an average-ish budget, and *_NO_* desire whatsoever to spend time in prison, I wouldn't dare. Not on my worst day.😂
But experimenting with inactive equipment. Now that i can get behind. Only problem is that *_decent_* - and that distinction *_is_* important - OTDRs themselves *_tend to be_* *_prohibitively_* expensive. Less-so used, but still so. particularly for anyone who isn't an ISP or fiber optic installer/testing, maintenance & repair company.
In any case, I wonder what effect there'd be by applying the blackest black or whitest white to optical fiber. Either along the jacket of the cable (Some light escapes the fibers and cables even though we can't usually see it, if you can, there's problems, or its just bent too far and there *_soon shall be_* problems), or *_gently_* around *_just_* the wall of the ferrule(glass tip; fiber itself is also glass, *_each_* the approximate diameter of *_a_* human hair.) - and/or maybe even inside the connector. Would it negate/absorb too much light? Or would it help the light better direct itself? Or using optical equipment in the blackest room, whitest room, or even an internally mirrored box. Would it even affect the readings at all? 🤔
Would also be a very good opportunity to potentially (probably long-distance) collab with Brainiac75, one of my other longtime favorites on this platform. He also rather enjoys lasers and a number of other interesting aspects of science and gadgetry. 😁
The music that started playing around 6 minutes was distracting. You don't need music for your fabulous videos.
Shouldn't there also be constructive interference sometimes in addition to destructive interference when you move the lase away from the mirror a bit? It should get brighter at some distances.
@@ConfidentialMeerkat you know it just recently struck me that I don't think I've ever seen a collab between him and any of the other big science/engineering channels...it never occurred to me how odd it was until this sketchy behavior surfaced. Now I'm wondering if these things are related
I thought people were exaggerating about how you handled critical feedback and I gave you the benefit of the doubt but after seeing how many comments were just purged I've lost a lot of respect. Many of which were still trying to be respectful while pointing out their concerns about a certain company.
This isn't a good look man. It isn't just about negativity.
@@ConfidentialMeerkat With that attitude, you prolly was shadowbanned from the site itself for spamming comments thinking it would change something, although I can see and reply to you...
got the notification that you replied to my comment where i explained the situation, so i went to read it and what’d ya know, the original comment is deleted/hidden now.
@@ConfidentialMeerkat I have this issue with the channel Wham Bam Tesla Cam, they auto-block any comment I make correcting them when they say "instant justice" and I tell them it's instant karma. Weird how may channels have auto-banning features like that.
@@biglewis7 I guarantee you've had "shadowed" comments you didn't know about. It happens on benign comments all the time that are just worded in some way the black box doesn't like. It does a better job removing harmless replies than the obvious bots we see every day.
What happened? I see a lot of angry comments, what for?
I heard the name of that company way too many times on this chanel, even though hundreds of people, including myself, made bad comments about it in the past. I'm out.
who cares about morals and ruined lives by awful therapist working on people on brink of suicide, when you can make a bank...
completely shameless, but yeah sure have my comment to boost your algo
Timestamp pls
It really is a shame. Just goes to show actionlab is only interested in money. You can even hear it in his voice he's not even interested anymore
@@DroneinHawaii it's not possible to live in a capitalist system without making money. You should know this.
@@Dirge4july you can still pick who to support.
Test, think I got blocked for making a comment about a certain company
comments about that subject are getting deleted for sure
@@ConfidentialMeerkatyeah, I was actually considering using BH a year or so ago until I discovered that little factoid. That's such a depraved move, selling people's secrets to advertisers so they can more easily manipulate people in an unstable emotional state...
What going on?
@@TheVoidAscensionist The content creator was deleting comments related to the SP-0N-S0R in the video.
@@chadl.981 ohh yeah the therapy one?
5:50 - who else wiped their screen - be honest 😂
Me lol 😂
Me broo 😢😂
Almost did!
Nope. I had gotten the gist of what he was repeating himself saying and was scrolling through comments just about still listening by that point. Only went back and replayed that time stamp to work out what you were on about
@@NipkowDiskhow tf can you almost whipe your screen?😂
There is a distinct lack of people in the comments that are mentioning a very specific thing from the video ....
This unsettles me.
Thats because comments are getting removed
@@Scarabaeus15 We are still talking about the hair, right? (nah, I'm joking)
At least we can be sure that each removed comment has been read first and they're aware of us being aware.
@@yerkeruiter nah, probably automated
@@Purrfect_Werecat Its automated. You can filter out any word you want on your videos if you have a channel
betterhelp
So if I could shoot laser light out of my eye, I would be immune against people trying to blind me with laser?
If they reflect your own eye laser back into your eye, then maybe. I don't think it works with another independent laser.
@@transklutz I guess it would depend on how much out of phase are the two lasers.
Yes and no . First you go blind forever. Then no more lasers can blind you
But for optimal efficiency use a 5k milliwatt or 5 watt 445 nm diode. Actually never do this . I'm joking as a matter of fact don't even look at the splash in the wall without appropriate goggles,it is equivalent to watching someone weld
@@HankyPankythedog As you said, don't do it with any lasers. But especially don't do it with blue ones. Technical stuff - blue light is created from UV light, which is invisible to a human eye. You can blind yourself or other person not even knowing you pointed that thing if it's damaged.
[edit]
Ok, forgot about green lasers - the thing I was talking about was shown at the end with a green and blue laser. That's what happens when you write comments half way through the clip 😁
That hair had me trippin
I kept wanting to wipe it off of my screen! 😄
Omg I literally paused the video and wiped my screen clean
Timestamp?
@@perpetualbystander4516 4:53
@@doctor9228 Thx!
james, don’t take their money.
Interesting video. Laser diodes are pretty much always fed with a control loop that samples some of their output. Without the control loop they would burn themselves out. Part of what you are seeing might have to due with this control loop, rather than destructive interference.
"Control Loop" = Pulse Width Modulation (PWM) Driver Circuitry. The actual "Light Amplifier" consists of partially silvered first-surface silvered mirrors.
That's a good point.
The somewhat more expensive laser pointers have OPC. If the reflected beam hits the sense-diode, the control loop will actively reduce the laser current.
The cheapo models don't have this they are simply current limiters.
There are several ways to control the Laser Diodes, the simplest is just current control, which is simple (might be just a resistor) and gives reasonable results, but you do get a moderate intensity variation over temperature. Optical feedback allows more constant intensity output. A cheap pointer might just use the current control and set the current low enough to never get above the allowed limits over temperature (or just ignore the rules ;) ), a better one would use the feedback, and that WILL greatly drop in intensity from the returned signal.
@@RichardDamon Good point. LOL
Not going to pretend to know what you're fully talking about, but I have to agree the chances of it being destructive interferance seems insanely small. Being able to cause destructive interference purely by hand would be effectievly impossible.
Well, deleting comments just shows that you don't have any counter-argument. You're just doing it for the money.
Are you sure it's the destructive interference? When you're perfectly in line, fewer observable photons escape, so the light appears dimmer. There MAY be destructive interference, but you only addressed that in theory, not in demonstration.
You can delete specific comments, but you can't stop us from leaving. Don't support the group with the green logo mentioned around 2 minutes into this video
Totally agree with you. They employ people who have NO IDEA how to do the_apy. The the_apist told me to "stop being a bad person" when I wanted to work on my borderline personality dissorder. That is beyond insanity. It lead me to the point of being suicidaI. They also charged me for that.
they were also caught selling "medicaI records" to third parties.
Why
Why?
@@realmrtenticlesthey take advantage of people who need help and don't actually help anyone
@@Eternal_Solstice that’s not good
"I'm not moving it at all, but it's flickering"
As long as you are alive, you are always moving at least a little bit -- whether intentionally or inadvertently
I was thinking the same thing. Whether thorough the blood pumping through the fingers or muscles and tendons stretching and what not, the laser beam would be constantly moving and changing angle. Still, he was able to keep it steady enough and close enough to observe an interaction.
Well, to be completly honest, even if you are not alive - a simple molecule, you will move. Heisenberg 101 😁
@@ogi22 Well said. I was going to reply that except even more catty. "To be even more pedantic..."
@@ogi22 except at absolute zero 😜
@@coreyduggan1246 yeah but he made it seem like the flickering was part of the effect rather than him definitely causing it. Perfect alignment should result in a circular interference pattern and no flickering
Interesting how it works best on red! Could the high frequency be why violet is hard to demonstrate this effect?
Why star
Membership of channel bro@@ปริญญ์พิริยะพรพิพัฒน์
0:20 nothing can be more interesting
Always remember to not look at laser with remaining good eye.
3:25 Fun fact: this probably only works with un-angled "UPC" connectors, like the one shown in the video, indicated by the blue connector housing.
There are also the much more common green APC connectors, which are angled at an 8° angle to reduce the amount of light reflected back into the fibre, making for a better connection.
They're not more common in the industry in general, but you see them ubiquitously in GPON installations because otherwise the reflected light interferes with the passive splitting system, you also see them on anything with a high power laser so that it doesn't burn itself out, or destroy the laser amplifier. Your average GPON also has a nice chunky laser on the head end because it's split down so many times, so they're just used everywhere on the system.
Bro actually banned the sp0nsors name lmao
why???
@@Local_747_fanThey're truly awful
@@Local_747_fan Cus they aren't so helpful as they say
Where
@@crishdeep in comments
After years, I'm out. Where the money comes from DOES matter, especially if you're doing publicity for a trap. Goodbye
can't wait for the action lab apology video 🙏😭
Wait what'd he do , no one is saying it 😢
@@vibaj16 ohhh I see , gues I'll have to check his X account or something
@@d.SAiNi. what's wrong here ?
@@PiusBamigboyeYou can probably search up a video about it
I’m gonna be honest Ive been laughing at this whole situation for 10 minutes 😭 Banning key words and removing comments is diabolical behavior lmao
5:42 the reflected light isn't non-coherent with the laser output light, it's actually pretty much in anti-phase.
Interference can only happen between waves that are coherent to one another.
The mirror doesn't jumble the phase randomly, it flips it about 180°.
If you shone a different laser into your laser, the two would be incoherent between themselves, and the effect would be pretty minimal, maybe even non existent.
That would also control the 'photodiode' variable he mentions in this title comment.
It collimates further on reflection into itself, so it isn't necessarily dimmer, we just see less rays, just like you can't see laser light in the air, unless there are particles in the air to diffuse it.
In audio engineering when you reverse the phase of an audio waveform and lay it directly over the un-inverted wave, you get phase cancellation. you'd think you'd get twice as much volume but you don't. In otherwords, you don't hear the audio at all. Could this be the same in this case? Waves of sound, wav e of light. Same right? Is the mirror inverting the wave of light?
That sounds pretty much correct. If you have a wave that is out of phase by any significant amount it will interfere. Beat patterns when tuning a guitar for example as you get them closer in tune you'll hear the interference as a rapid modulation in volume that will occur slower and slower all the way until it's perfectly in tune. If the wave is antiphase it will cancel perfectly and no power will be transmitted.
I immediately jumped to wave cancelation for light.
Dropping out. Yet again you use that company while it's *dangerous* to it's customers, it's consistently so, and you know it by now. You are willfully causing harm to your viewers.
Almost as dangerous as a witch hunt over something you have zero evidence for. Cry harder.
I see these comments what about the company? What's happening?
@rubrtt absolutely nothing. What you're seeing is just a bunch of self-righteous losers pretending there's a crusade to be had because they're bored and have nothing better to do. Absolutely nobody who claims there's an issue with the company has any real evidence to support their claims. It's all anecdotal "evidence" referencing the *one* time someone had a (what *seems* to be) legitimate complaint about a lack of credentials preceeding a single incident.
@@rubrtt Abuse of patients, abuse of therapists, sharing of personal data, etc. They are *incredibly* bad and dangerous.
@@TuxieBSOD dam
Try the same trick with a helium-neon gas laser tube.
Beam will get much, much brighter when you line up the mirror correctly (front surface only!)
It's a very sensitive adjustment...we had to use clamps and the like to make it work.
You should try another types of lasers. Diode lasers have optical feedback very often. A built in photodiode to control optical power of laser. So flickering is feedback work.
He-Ne Laser tubes will start "pumping" or pulsate if u do so 😊
Remember, WorseHelp can't get him to remove dislikes.
Too bad yt removed viewers' access to seeing dislikes
@@Kevin-nr2jc There are still extensions that let you see dislikes.
What are you talking about???
TH-cam already removed those. Unfortunately...
@@lorrainebrunner2490 On Firefox there's an extension that brings them back.
@@lorrainebrunner2490In pc you can use extensions to see dislikes
PLEASE for the love of god use a different paid section. There are better options that don’t violate your privacy. It’s getting ridiculous at this point, it’s not like you don’t know what they’ve done and instead having yt delete comments.
What did they do??
@@hhf39p Roughly, they are straight up making people to *end*
Literally
Policy
@hhf39p they caused an intergalactic destruction over the span of thousands of years... millennial long tragedies...
maybe you could have tried sloly changing the distance, to see if the phase change affect this phenomenon
Can't control the hand with nanometer precision, so the effect might be something else.
0:11 gives me White diamond vibe😂
I love the Steven universe reference😊
(⚪️_⚪️)
If Steven universe dies I'm gone
STEVEN UNIVERSE FAN SPOTTED?!?!?!? 🤭🤭🤭
STEVEN UNIVERSE MENTIONED 🗣🗣🗣🗣🗣
I had the opportunity to talk with Art Schawlow, Nobel winning physicist back in the early 80s in Palo Alto. He carried a hand held laser with him for demonstrations when lasers were new. Great man with child like curiosity.
Some types of red laser diodes contain an internal monitor photodiode (on which some of the emitted light goes), to allow feedback on the optical output power.
Presumably, the laser diode emits less power because the returning beam hits the monitor photodiode, causing a reduction in the drive current of the laser diode 😊
interesting, that could be the reason as well
@@TheActionLab please do research about your sponsors before you put them in a video. You with close to 5M subs should know that.
@@gamingmitkeks1550what’s the drama? Explain to me
@@TheActionLab it likely is, I tried this about a decade and change ago with a cheap laser pointer, and rather than dimming, the laser diode just died within seconds when I got the angle perfect to shine back into itself.
try maglev induction coil ore metallic gold silver iron separation from non-magnetic non-conducting sand. maglev induction can also optionally melt the floating stuff.
BetterHelp is sponsoring this video?
5:00 Ummm, I think you're overthinking some of this... The laser light is invisible unless it bounces off of something. When you shine it directly back on itself, it's not reflecting off of the frame and PCB, thus appearing to dim the beam.
Otherwise 💯🙂
what if around hole very dark paint?
*Intrusive Thoughts Getting Really Strong
The Action Lab : "Yes"
For Real.. 👽
This channel is just the right amount of science and dumb ideas.
@@markm0000 Indeed.. 😁
Radio Tower Climber here... With that identical fault indicator flashlight.. it breaks the light up a bunch and it not a focal laser... shine it on the wall you'll see the spiral.. It goes through something that alters the light path so that the laser is shined throughout the entire fiber optic in a way that our testing modules can use to scan the fiber for dirt and fractures more efficiently that a solid light beam.
What kind of work position is this... Radio Tower Climber..
@@KyryloHryhoriev The Job dons many names.. for instance are you specializing in point to point, repeater/communications, cellular, government specialties like ATAK, or are you the general structural specialist working on the tower itself (paint, lights, maintenance, construction, deconstruction), or are you just a ground guy working ropes and shelters doing all the ground inspections and punch outs.
There are some people whose entire job is just driving around with a $20k fiber tester, or RF mapper running tests for companies that either can't afford one, or don't want to rent a unit because it's not a common project use tool. Anyways, I was just pointing out they tried to use a laser in search for a solid beam tool.. I've got that exact light in one of my climb bags and can speak with 100% confidence when I say it's diffused.. If he shines it on the wall he will see the spiral we use to spread the light around in a way that the machines can differential dirt and fractures in the fiber. The climber attaches it at the OVP junction box at the top of the tower (in my use case) and the tester connects at the bottom in the shelter where they insure it wasn't damaged during installation. It's not uncommon for the hybrid cables on a cellular site to cost upwards of $50k, and we brunt a lot of that liability while installing it so we have to cover our asses and document it's condition at the time before and after installation.
4:22 - Um, pretty sure a human can't hold "still" at that infinitesimal scale of particles... your "still" is still a 9+ earthquake on the Richter scale to a photon.
you are correct, in the Michelson interferometer if you lightly step on the concrete floor the interference pattern moves.
if you wanted to optimize for as little movement as possible youd need vibration damping, a place far away from large moving objects
It doesn't have to be at "particle scale", because coherent light is not single particle (although its generated that way). What you should measure against is something called the "coherence length", exactly because coherent light is made of many photons, and is in a certain way macroscopic (not always, but in this case yes).
That's why making single photon emitters out of laser light is basically impossible.
I think he just misspoke, his slight movements are in fact the reason it flickers
@RyanAumiller that's obvious, why point it out? Unless you are autistic and take everything literally? Or pretend to, so that you can try to make others feel stupid? I've been there. I recommend growing out of this phase ASAP.
Just want to say that this is the best video on how lasers work. I have not been able to understand it before
Actual laser diodes have completely different geometry and construction than shown. No mirrors, optical cavity, emission is perpendicular to the layers, not along the interface. See the Wikipedia article.
joined 17 years ago.... ur likethe oldest user ive met
Not really. Are you talking about VCSELs? A classic semiconductor laser has a cavity parallel to the emitting active layer. ☝️
You could try to make the feedback less extreme by using an optical grating. The littrow configuration is when you send the first diffraction order back to the grating. Order zero is used as an output. The power goes down well above threshold, but the the threshold reduces. We use this a lot to make very coherent lasers and tunable lasers out of simple laser diodes, they are called ECDL
5:48 - I know I wasn't the only one trying to get that hair off my screen right here.... 😂😂
I was to omg😂😂😂
Simple at home experiment. I used a mirror in my bathroom and put a bit of cigarette smoke in the room. I stood about 8-10 feet away from the mirror and aimed my red laser pointer at the mirror. It took a minute and a steady hand, but I was able to reflect the beam back to the pointer at the aperature. The beam was visible as a dashed line, not solid but with gaps immediately displaying the interference pattern. I was able to do this even without steadying my hand on an object. Really cool looking!
6:25 Hm, so if you wanted it to concentrate the light further, you'd actually want to redesign the laser so that the beam circles back around to the back and fires in at the same direction as the new light being added. Of course, I highly doubt the effectiveness because there's only so much concentration you can get. Entropy and all that.
Great video! I think the dimming effect when reflecting the laser back into itself is due to optical feedback causing mode competition in the laser diode, not destructive interference. Destructive interference would require precise distances and phase alignment, which doesn't seem to be the case here. The back reflection disrupts the laser's operation, leading to reduced power output and instability. This phenomenon is well-known in laser physics, and optical isolators are often used to prevent it.
Thanks for this video, i had this question in my mind the whole life
I too used to wonder what will happen when a laser is reflected into itself
Actually tired it... i thought i damaged the pointer (it was cheap one like under $1)
The thing that most laser explanations leave out is that stimulated emission depends on the number of photons already in the correct state.
7:42 - who checked their phone? lol there are so many easter eggs in this video.
This sounds very similar to standing waves in audio, where you have areas of dead spot where the waves cancel each other out. Very interesting that it happens to light as well. Thank you
Ok…..thats is the best explanation of how a laser, actually functions to focus a beam of light….Thank you for that. I’ve honestly never heard such a precise and simple explanation. Again….THANK YOU
I always assumed it dimmed because it was swamping the photodiode in the regulator/feedback circuit.
I assumed its because less light was leaking out to the camera
if i'm correct the light doesn't really cancel itself out into nothing, i know that when two opposing electromagnetic waves collide (let's say p1, p2), the result is either p1+p2 or p1-p2, so the total energy stays the same, and assuming p1=-p2, no light is actually lost, it just doubles half and cancels out half the light. you can see it by the experiment you showed of combining the lazer, it had a corresponding light pattern with the same total energy, some canceled out some amplified. (feel free to correct me, am a silly 17yo currently)
5:00 I tried wiping my screen 😅
A thought here; does the mirror reverse the wave? If the peaks and troughs are out of phase the intensity will dim. The laser diode will still produce more than is cancelled so you still get some light.
we got the action lab getting canceled before gta 6 😭🙏
Ohio
No need to cancel this guy... There's no way he did anything wrong.
The sp0ns0r @@michaelwicker9538
@@michaelwicker9538the sp0nser
@@michaelwicker9538 He is protecting the company that is selling data of people that arent doing well and before you start saying OTHER COMPANIES ALSO SELL YOUR DATA . Yes other companies do that but THAT COMPANY (My comment will get deleted if I say the name) isnt allowed to do that by FTC because imagine if you went to psychologist and you tell them all your problems but insted of keeping it for themself they will tell to all of petients how would you feel about that
Most lasers, even relatively small lasers, have coatings on exit optics designed to be polarising, this is not only to reduce optical feedback it increases output stability. For high power lasers Faraday isolators are used in the output optics to introduced a 1/4-wave phase shift. Without these features the workpiece / target suffers optical banding as the working distance between the target and the laser generator varies by the wavelength of the system. In high power applications the system is actually designed to be slightly off-axis as well as polarised to introduce yet another safety feature.
Like audio waves, if you invert the phase of 2 identical audio signal you get silence.
Yes. Have you ever tried it?
@@randyg.7940 sure
The cable length and whether you're using multi mode or single mode transmitter/receiver make a difference. Minimum length is 3 feet if I remember correctly, and that is for multi-mode short range fiber. I don't remember what the minimum for single-mode long range fiber is. I work in IT and I have have had transmitters burn out because the wrong length of cable was used for the type of transmitter.
3:06 thought I had a hair on my screen😅
My training to get it away 😂😂😂😂😂😂
Me too. Was trying to flick it off, lol.
Fun fact: An older technique for producing ultrashort laser pulsed uses an external cavity and back-reflection into the laser to mode-lock the laser. It's called additive pulse mode-locking.
4:10 maybe there is a fast cancellation going on here
😂
Great demonstration 👍🫡🤝
this channel has rly been a life changer for me through my childhood, such a big reason of my love for science today♥
What type of fiber did you use? Just regular OM3/OM4?
I will say that when it reflects in itself - we see it dimmer because footons do not reflect to camera lens, but go in. We see only reflection, 90° - no reflection/minimum reflection.
I am glad I am not the only one saying this.
If you shine a laser at a piece of paper with a hole in it, it suddenly looks a lot less bright when you shine exactly through the hole.
Exactly with you on this. Chance for observation off axis seems the likely cause it seems darker. It's just not spilling into the environment much for us to observe.
Discussing light or fold-out couches?
One of the fun experiments I saw in the 90's was putting an argon water cooled lasing into the lesser reflector of a krypton water cooled to make white light.
Not very efficient but would still work.
Harmful sponsor's earn unsubs
Yes indeed
Luckily, I already have a laser light and I used my hand watch back shiny side for reflection. It really works and a very fun experiment
1:27 It's an abbreviation?!
Which means we been pronouncing it wrong the while time
I like watching your videos. Been with the channel when there were around 20K subscribers. You make us understand, even basic things have great concepts and physics involved.
Better help
When waves meet at a destructive interference and cancel out, where does the energy of both waves go to?
what happens if you reflect a high powered burning laser back on itself? will it destroy the emitter?
no, as you have seen in this video the light will destructively interfere.
The video we've all been waiting for
Well this warrants inquiry into more serious questions with heavy ramifications. Should the word L.A.S.E.R. be allowed on the scrabble board if it's officially an acronym? Would changing the spelling such as lasers or lasered constitute keeping it on the board. Do I really have to award Jennifer those 6 points? We pronounce S.C.O.T.U.S. and P.O.T.U.S. as words, but they're not allowed. Would this require a rule change for modern time? No Jennifer, I will not stop typing! I'm letting all these people know your threatening me with a frying pan. If you even think about hhhhhhhhhhhhhhhhhhhhhhhhhhhh. Hey guys! Jen here. Laser stays on the board!
Bruh
What is happening is cycling through thousands of interference fringes per second. You should try this with recording off the photodiode included with the laser.
Also the lower output is also due to the photodiode seeing the reflection, there is a circuit which regulates power output from its feedback photodiode.
I thought it was my screen that had the hair😂
I done that before too with lasers. If you don't destroy or warp the mirror of the process it almost seems like it penetrates into some kind of weird mirror dimension.👌
Can you stop sponsoring that company? It sounds like people are leaving because of it… I dont really know anything about this situation, or why people won’t say the name of the company, or what the company even did, but I don’t want you to lose viewers cus u have really great videos :)
He's DeletingComments about the company.
its because the company has a very bad reputation and its known for doing some illegal stuff. it doesnt even have VerifiedTherapists
This is a very nice demo. It's amazing that you can see these effects with a hand held beam. I am interested in the ability of a feedback laser to increase the coherence length of a blue diode laser. For holography. Special diodes with an anti reflection coating on the output mirror enables the laser to be frequency sharpened in a longer cavity. A high power inexpensive diode system would be a great boon to holography.
05:40 - Did you try to brush that little piece of hair off your computer screen too?
Hey, that was not there a moment ago! what the.... it's in my screen! hhéé,. nice illusion
Or the laser diode has a monitor photodiode monitoring the output of the laser diode on the other face of the laser chip. By shining light back in the monitor photodiode thinks the laser is outputting more power than it actually is. Hence the drive circuitry turns the current down....
0:20 What could it be more interesting than destroying the world? 🤣🤣🤣
Destroying the world with physics… it’s giving Randall Munroe vibes :)
Destroying the woke 🤟
Nothing.
We're building the guns from Star Wars
@@vibaj16 amazing profile pic :)
You actually just do not see it as much when it focuses stronger at the tip. I tested that on a sensor years ago. As it gets more focussed it narrows more to the center. It works a little different with each type of laser. It strongly depends on what you are using to create that light with to though.
Deleted the comments with the name of the company supporting the video knowing they have a bad reputation. Lost a subscriber.
A few more than one subscriber
Actually fun fact, you can measure the light that comes back and use the measurement to calculate the speed and distance of the object the laser is pointing at! I didn't believe this was possible at first, but I made a video on my channel explaining the physics of exactly how it works! It's very cool, there's a few laser sensors out there that use this mechanism!
Wonderful vid! ❤🎉
would it be possible, that you just reflect more light onto the monitor diode, which is part of the feedback loop of the power regulation of the laserdiode? The control loop would then reduce the power, because the monitor diode detects more light than usual.
i'm out of the loop, what's wrong with the spons0r of the video?
betterscam
they do more harm than good. terrible therap1sts. he’s had them sponsored many times despite this.
I tried BH (the sp0ns0r) services. They employ people who have NO IDEA how to do therapy. The therapist told me to "stop being a bad person" when I wanted to work on my borderline personality dissorder. That is beyond insanity. It lead me to the point of being suicidaI. They also charged me for that.
they were also caught selling "medical record" to third parties.
The stance of that app was that they are not responsible for checking that the therapist are real therapist or have license "it's responsability of the user to verify that the people is really a licensed professional" they did no return the money of inconforme people, later on they backpedaled some of this but only lip service
@@stormie_skies They are the rapists.
Does it suck the power less from the battery when that happens? Or just turns the energy lost into heat?
1:43 Please wear laser safety goggles when playing with lasers
lol
no
What about pet lasers?
Right
Ask Dr Science.
When the light flickered and dimmed; did you change places with your reflection in the mirror?
Seriously, I really enjoy your content creation. Thank you!
Bros been yapping for 2:52 bruh
Before you even did this experiment i said it will be out of phase making it go dim.
Bingo!
Fire it through a tiny hole in a mirror onto another mirror then back through the hole in the mirror. Measure the wavelengths and set your laser to out of phase distance
Ngl, the hair on the mirror fooled me 😂
Even without destructive interference, for example if you happen to match the distance so that there is constructive interference, you are still limited in lasing power by number of lasing centers (atoms). You just can't get more photons than the number of centers that undergo stimulated emission.
Geez... my former laser tech experience makes my spine shivers when you shine laser on that mirror... And touching a mirror surface with fingers? Tsk, tsk. If I did that with a real cutting laser mirror, I would be in trouble 😉 Yes, way back then, when CO2 lasers were a thing, laser techs had to clean and set up mirrors at least once per year.
I don't remember now perfectly, but there was a possibility to damage a resonator when cutting highly reflective metals by getting the beam to flash back. I guess if you have a few kW of power in a cutting laser, it looks a bit different then in a pointer. 😁
I tried this way back with a cheap laser pointer, it just died too, though just much less spectacularly than a few kW.
Diode lasers can be built only from semiconductors that have an exciton state in their band gap. It is only when the exciton density reaches a threshold that the semiconductor amplifies light. Below that threshold, stimulated emission only reduces the attenuation.
And amplification evidently is not possible in diodes without excitons. Without excitons you only have a light emitting diode.
Reflecting light into a low power laser diode can cause mode hops and even lead to chaotic behavior, but it will not damage them. But, a powerful laser can be damaged if even a small part of the light is reflected back into it.
Thanks for this information action guy!