First build -optical power problem

Torquize · Jul 27, 2013

Hello!

So I decided to build my first laser (and yeah, I made that first mistake I choosed high power...)

I bought PLTB 450 diode ->
Brand New OSRAM 450nm 1.4W Blue Laser Diode/TO18 Package/PLTB450| eBay

Heatsink ->
1845 House Glass Lens TO18 5.6mm 405nm 445nm 450nm 473nm Blue/Violet Laser Diode| eBay

Build my own driver by using LM317. By measurment on that diode I'm at 1,26A / 4.5V.

BUT...optical power of laser beams is too weak, definetly not 1.2W. Could it be just unfocusable beam? It looks like this right now...

Thank you for reply and sorry for my Borat-like English

DTR · Jul 27, 2013

What lens are you using? What was the actual output on the power meter?

With the PLTB450 and a G-1/2 you will see about a 1mA-1mW average. With a three element(Aixiz) lens it will be about 25-30% back of theat.

Torquize · Jul 27, 2013

Lens are specificted in description, second link, like: "This is a house with coated focusable glass lens (three layers); Glass/three layer lens/for 405~450nm laser diode.

I don't have optical power meter, just use volt&amper meter

WizardG · Jul 29, 2013

And what are you using for a power supply? A '317 linear driver will require about 2 volts over the laser diode's forward voltage to deliver full current.

Leodahsan · Jul 29, 2013

(refer to post #4)
and
Have you measured the driver using a test load?

Blord · Jul 29, 2013

Could you show us the output of the diode without the lens ? I want to see the dot pattern.

Torquize · Jul 30, 2013

Hello guys, thank you all for your help, I really appreciate it.

@WizzardG, Leodahsan:

Power supply is simple linear source 10-11V /2A, using LM317 as current limitter @ 1.2A...after test loads looks power source good - I have bachelor in electroengenering so this shouldn't be problem. (but, yeah...sometimes it happens)

@Blord:

I tried it, but I don't have good camera and perfectly opaque area. So here is result:

Zom-B · Jul 30, 2013

Pattern looks good to me.

As for power estimation, aim at your (white!) ceiling during the day (with or without lens). If you see a blue haze on your desk, you're fine. If it's nowhere near that, you might have an expensive LED.

Leodahsan · Jul 30, 2013

Maybe an ammeter in the output should measure the current during operation and see if everything's ok.

cheech226 · Jul 31, 2013

Looks plenty bright. Don't let it get too hot, doesn't look like a lot of heat sinking on the diode.

First build -optical power problem

Torquize

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DTR

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Torquize

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WizardG

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Leodahsan

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Blord

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Torquize

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Zom-B

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Leodahsan

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cheech226

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