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Unknown 405nm Diode from Blu-Ray Burner

Tuxifix

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Dec 1, 2018
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Hello fellow laser enthusiasts,

I have kind of a stupid problem. Quite a while ago I got a defective blu-ray burner (from a Sony VGP-PRZ20A docking station), from which I saved the diode and threw everything else away. At that time I tried to test the diode, but failed probably because I was too careful with the voltage and thought the burner was likely just defective because of the diode. Anyway, yesterday I tested it again, and got some light out of it. The field of view is about 15cm +- 50% with a distance of 20cm +- 50% to the bare diode (sorry, I didn't measure). It was operated for a few seconds with 50mA.
Diode 405nm klein.jpg

The problem is 1) I cannot tell if the beam profile looks normal or if the diode went LED on me. In that case I could stop worrying about it. 2) The most stupid thing is that I did not write down what kind of blu-ray burner that was (even thouth I do not know if that would have helped) and have thus no idea what diode it is. Is ther any way to find out with how much current it can safely handle?

Best regards,
Tuxifix
 
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Immo1282

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I've an untrained eye - but it looks LEDd to me... Aren't Blu-Ray diodes 405nm i.e. purple?
 

diachi

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Beam profile looks fine.

I've an untrained eye - but it looks LEDd to me... Aren't Blu-Ray diodes 405nm i.e. purple?


They are violet (not purple, purple isn't the colour of a wavelength in the visible spectrum ;)) but most cameras have a hard time "seeing" it properly, further, 405 causes just about everything to fluoresce brightly. Plain paper for example will fluoresce a bright blue colour (like above) when exposed to 405nm light.

OP, looks like you're just running the diode whilst holding it in some crocodile clips. I do not recommend you continue doing it that way, at any sort of power level that'll quickly kill the diode. They need heatsinking.
 

Tuxifix

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OP, looks like you're just running the diode whilst holding it in some crocodile clips. I do not recommend you continue doing it that way, at any sort of power level that'll quickly kill the diode. They need heatsinking.
You are absolutely right. I was just increasing the current till I saw light and switched it off within 2s. Then once more for the photo. The next time I run it will be in a proper heatsink which I do not have right now, but before buying one I wanted to make sure the diode works.
 

Immo1282

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Fair point diachi - I'd not considered that the wall might be flourescing :)

But yep OP - it's not good to run LDs out of a module.
 




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