Driving a laser pointer below its rated power

cyberFish · Jan 23, 2013

Hi all,

A Newbie here. I am planning to buy this laser diode : http://www.thorlabs.com/Thorcat/11900/L808P200-SpecSheet.pdf

It is a 200mW diode, but depending on circumstances, I might need only 50mW of power. I was wondering if it is possible to make this laser diode work at 50mW? If so, how low of a power can this diode work at?

I tried to look up this simple question in forum, but couldn't find it anywhere. My apologies if this is a repeat.

Thanks!

Cube777 · Jan 23, 2013

Just run it at a lower current than the recommended current. That way you get a lower power, sorry can't open PDF right now so can't see if there is a power graph. Just speculating here but i think if you run it a a quarter of the recommended current it should give 50mW.

mojo_1234 · Jan 23, 2013

sure - and if your diode driver circuit has something like a pot - your're lucky!

You should drive the diode above threshold, below no lasing. Please consider the lasing wavelength also depends on diode temperature (-> current).

cyberFish · Jan 23, 2013

Thanks for the replies! I am making my own current control circuit to drive the diode, so it should be easy for me to control the power input.

lasersbee · Jan 23, 2013

You can basically supply any lower current than the spec sheet
Maximum.
As was mentioned above....
You must of course be above the Threshold current stated on
the spec sheet to have any Laser emission.
Below the Threshold current your LD will essentially be an LED
with no Lasing.

Jerry

You can contact us at any time on our Website: J.BAUER Electronics

Fiddy · Jan 31, 2013

you do realize the LD is 808nm which is very very dul/invisible the human eye?

Driving a laser pointer below its rated power

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