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90W 905nm Laser Diode for $23

Jimmymcjimthejim

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Yes, you read that correctly. 90 watts.

Get it tomorrow for $23:

It seems that these diodes are used for lidar and rangefinding. Any ideas what else they could be used for? Any crystals that can be pumped with this?

The thermal resistance is 160K/W and max temperature is 85C, so you can only run it at (85C-25C)/(160C/W)=0.375W continuously (input power). But still, 90W for 100ns is a massive amount of power.

Throw in your thoughts!
 



Alaskan

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I bought some old used laser rangefinders for 5 dollars each which have that same diode as well as a driver board in them which all worked fine, just the LCD display was very faded and due to that were warranty returns to the manufacturer. Although that diode can peak at 90 watts, the pulse duration is extremely brief and thus the duty cycle extremely low, I can't think of what they could be good for beyond what they were designed for as a time of flight source for LIDAR, maybe signaling little green men in UFO's, but pumping crystals, I just don't see how they could be used that way but now that I've written that, doubtless someone will know a way.

Here's a video I took of the output from a distance of several hundred feet away with a camera which is sensitive to infrared.:



(Above YT video) Near the end of the video I show what the output looks like to the camera in my bathroom with a fogger which produced the thickest fog I could make, without a very thick fog, the long beam output could not be picked up from the side by the camera, but with it, the output looked like a torch.

(Below) I don't see these used units listed on ebay by the manufacturer now, but here's what is inside:

 
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Anthony P

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There is some info on powering these in "Light and Its Uses". If I recall there is also an old article in Radio Electronics magazine using an SCR circuit.
 

Jimmymcjimthejim

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I bought some old used laser rangefinders for 5 dollars each which have that same diode as well as a driver board in them which all worked fine, just the LCD display was very faded and due to that were warranty returns to the manufacturer. Although that diode can peak at 90 watts, the pulse duration is extremely brief and thus the duty cycle extremely low, I can't think of what they could be good for beyond what they were designed for as a time of flight source for LIDAR, maybe signaling UFO's, but pumping crystals, I just don't see how they could be used that way but now that I've written that, doubtless someone will know a way.

Here's a video I took of the output from a distance of several hundred feet away with a camera which is sensitive to infrared.:



(Above YT video) Near the end of the video I show what the output looks like to the camera in my bathroom with a fogger which produced the thickest fog I could make, without a very thick fog, the long beam output could not be picked up from the side by the camera, but with it, the output looked like a torch.

(Below) I don't see these used units listed on ebay by the manufacturer now, but here's what is inside:

Very cool. I knew I couldn't have been the first to know about these. I'm surprised that there aren't more applications for this diode.

There is some info on powering these in "Light and Its Uses". If I recall there is also an old article in Radio Electronics magazine using an SCR circuit.
Apparently it's not too difficult to drive these. Charge a capacitor and use a MOSFET to connect the capacitor to the laser diode.

This module has the capacitor and MOSFET built in the package.

 

Alaskan

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I was tempted to buy a few of those laser diodes on ebay, but after finding them inside those golf laser rangefinders which already had a board to make them run included, as well as some nice AR coated 905 nm lenses inside, never did so.

I did however buy some of the 850 nm Osram nm flat pack diodes a few years ago, still have them, somewhere. The Osram 850 diodes are 14 watts peak pulse which due to having less atmospheric loss at that wavelength (compared to 905) were used in some of the first golf laser rangefinders available.

Why now use 905 nm instead? My guess is high power pulsed laser diodes at 850 nm cost more to produce, so I believe the industry went to the much higher peak power 905 nm diodes instead because their extra power more than overcomes the higher atmospheric loss at that wavelength. There may be other considerations involved for why they went to 905 nm, perhaps detection and resolution, or longer wavelengths behaved better, I don't know, pure speculation on all of that, it could have just been money, if 905 is cheaper to produce at high peak power, as I suspect happened.

I believe the diode in the V400 (link) rangefinders I bought use this 75W radial packaged model:


Also, not cheap, but here is a link to some pulse laser diode drivers: https://directedenergy.com/laser-diode-drivers/

I am attaching the data sheets for the 75 watt radial & 70 watt flat package version and OSRAM's Operating the pulsed laser diode SPL PLxx application note # AN107 to this post.
 

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Jimmymcjimthejim

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Alaskan

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It's not of much interest to members here, this diode keeps coming up ever now and then, one member even went to the trouble of getting one fired up to discover it didn't even warm anything, much less burn. Average power is a whisper, won't do that, not even warm enough to feel.
 




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