Technology marches on. Thank you for taking the time to disassemble and provide us with microscope views of the laser diode. Interesting pattern on the blue tack as well. Regards, David
made one with cheap modules like tp4046, single use vape pen battery and the case was a cap of a lipstick. So, my cat and also the girlfriend likes it. Should be recommended for anybody who has a cat or for kids in order to intruduce technical culture.
Could you show the 'weird' IV curves on your nice curve tracer of the laser diodes you are used to? For comparative educational purposes. Does threshold current typically manifest in the IV curve?
I bought a whole bunch of these key ring laser pointers from a flea market. My key ring lasers originally operated from 3x LR44 button batteries. For an eye tracking project, I modified the laser to operate from an LM317 30mA current limiter (12VDC input), and inserted a diffraction grating into the lens, resulting in a display grid of red dots on the wall, to which the person would look at each dot in turn. The eye movements from this laser grid calibration would serve as a datum for the main eye tracking video of the intended scene stimuli.
Same thing with laser pointers I got from the dollar store. I just took them apart and replaced the battery with a 4.5V supply, and I can run it off of an AC adapter.
I took apart laser diodes from the dollar store 20 years ago (in the early 2000's) and they were exactly the same - just a resistor and a bond wire down to the laser, all stuffed into a little brass housing. Maybe the diodes are more robust now??
Cool video. Maybe I'm misremembering, but I think that it an earlier video about laser diodes you said that using a constant current source to drive them wasn't sufficient. The implication being that you had to feed-back the photo-diode in the package to keep things under control. I was chatting with a laser physicist colleague recently who was saying that for his application they use constant current sources as it minimises noise. Was there a particular application you had that required getting as much energy out of the laser without being too concerned about noise?
Oh yeah, I've got a bunch of diode lasers. Including a 40-watt (that only actually puts out 20), which I got for 50 bucks brand new! It's got a big heatsink and fan.
Would be cool if you could do a circuit on pulsing both L.E.D.s & LASERdiodes to the extreme to see HOW BRIGHT you could get them and what kind of electronics driver circuitry ?
What's the nature of the failure mode when a LASER diode ceases to provide a bright, coherent beam and appears to become a regular low-energy LED? What exactly happened? I've been curious about that for years.
it's complicated, in order to lase it need to have all the light (EM waves) traveling in sync.. this is coherence. any asymmetry in the cavity will break this and it is just an LED.
Heh its not even ball bonded its just wedge bonded... lol. Cheapest of the cheap. Also if you are not interested in constant optical powrt why would you need feedback?
You wouldn't happen to have an older laser that you could put on the curve tracer, since you mentioned the difference?
Technology marches on. Thank you for taking the time to disassemble and provide us with microscope views of the laser diode. Interesting pattern on the blue tack as well. Regards, David
DIY cat toys will be so much more affordable these days! Thanks for the heads-up!
lol
made one with cheap modules like tp4046, single use vape pen battery and the case was a cap of a lipstick.
So, my cat and also the girlfriend likes it.
Should be recommended for anybody who has a cat or for kids in order to intruduce technical culture.
Could you show the 'weird' IV curves on your nice curve tracer of the laser diodes you are used to? For comparative educational purposes. Does threshold current typically manifest in the IV curve?
I bought a whole bunch of these key ring laser pointers from a flea market. My key ring lasers originally operated from 3x LR44 button batteries.
For an eye tracking project, I modified the laser to operate from an LM317 30mA current limiter (12VDC input), and inserted a diffraction grating into the lens, resulting in a display grid of red dots on the wall, to which the person would look at each dot in turn.
The eye movements from this laser grid calibration would serve as a datum for the main eye tracking video of the intended scene stimuli.
A video on how to mount these on a shark would be appreciated. 😉
Carefully.
This was news to me also... I usually follow the physics side of these. But apparently I haven't look into it for a long time.
Ha! The markings on the board suggest notes. Would it be a laser harp or other instrument, possibly like the ones used by Jean Michel Jarre?
th-cam.com/video/A7HLS2dXoo8/w-d-xo.htmlsi=I07gmq1uwzl6nLWD
Interesting indeed, have you tried pulsing them with more current, for a higher brightness?
Same thing with laser pointers I got from the dollar store. I just took them apart and replaced the battery with a 4.5V supply, and I can run it off of an AC adapter.
I took apart laser diodes from the dollar store 20 years ago (in the early 2000's) and they were exactly the same - just a resistor and a bond wire down to the laser, all stuffed into a little brass housing. Maybe the diodes are more robust now??
Are they actually lasing? Is the speckle pattern present? My guess is they’re simply being run current limited, without optical feedback or a driver.
yes they lasing, coherent, and lots of speckle.
Cool video. Maybe I'm misremembering, but I think that it an earlier video about laser diodes you said that using a constant current source to drive them wasn't sufficient. The implication being that you had to feed-back the photo-diode in the package to keep things under control. I was chatting with a laser physicist colleague recently who was saying that for his application they use constant current sources as it minimises noise. Was there a particular application you had that required getting as much energy out of the laser without being too concerned about noise?
1000's of uses for lasers.
Oh yeah, I've got a bunch of diode lasers. Including a 40-watt (that only actually puts out 20), which I got for 50 bucks brand new! It's got a big heatsink and fan.
Would be cool if you could do a circuit on pulsing both L.E.D.s & LASERdiodes to the extreme to see HOW BRIGHT you could get them and what kind of electronics driver circuitry ?
What's the nature of the failure mode when a LASER diode ceases to provide a bright, coherent beam and appears to become a regular low-energy LED? What exactly happened? I've been curious about that for years.
it's complicated, in order to lase it need to have all the light (EM waves) traveling in sync.. this is coherence. any asymmetry in the cavity will break this and it is just an LED.
lazers , phazers. tazers, blazers. disco fever! OMG! get a load of that machine! it's a thing of beauty!! how many fellas R standing in line! ha..ha..
I just heard about the release of consumer laser diodes @ 593nm. What are your thoughts?
They are still expensive so I don't have one. I don't know what technology they use. probably the same as green doubled lasers
Careful! Brainiac yt channel explains how dangerous these cheap lasers are since they emit light also in non visible spectrum.
red ones? you are thinking of green ones.
@@IMSAIGuy yeah it's the DPSS-doubled green ones that give up 532 and 1064nm. There are not-frequency-doubled (non-DPSS) green lasers now too.
@@stamasd8500 I've seen yellow too but now sure what materials it uses for that.
How can we be sure they are actually laser diodes and not just bright LEDs?
the light is coherent with speckle. LEDs don't do that
Are they lasers or are they LEDs with an optical lens in front of them?
the light is coherent with speckle. LEDs don't do that
Heh its not even ball bonded its just wedge bonded... lol. Cheapest of the cheap.
Also if you are not interested in constant optical powrt why would you need feedback?
The feedback would be used to control the output and stop 'runaway' not solely for control of output power.
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