405nm laser diode threshold current measurement

This is my new 405nm laser diode. It was sold as "150mW" which seems to be way beyond specifications... yet this is the highest power rating currently available from blu-ray / hd burner drives. When comparing the 32-35mA of laser threshold current to Sanyo datasheets I conclude that the diode might be constructed to have a nominal output of ~40mW and an absolute maximum rating of 80mW.

As I limited the current to 100mA using a LM317 and an 12.4 Ohm resistor I can not tell how hard this diode can be driven with adequate thermoelectric cooling applied... unless otherwise known, I will be running this little diode at 100-120mA with a standard active heatsink.

ps.
The nominal operating current seems to be somewhee between 50-65mA, the LD seems to be able to handle 30mW output.

Category:

Science & Technology

Tags:

• 450nm
• blue
• laser
• diode

[CxC2007]

Again.....

Is that a Uranium glass bar ?

I have some marbels, and the efect is great with the laser..

[hboy007]

it's a test tube filled with diluted fluorescein dye, I am using it for all my UV laser experiments

[CxC2007]

I bought in Ebay a blueray laser with adjustable lenz, but without current source, but they give you the materials and the schematic to build one of 10 components, I calibrated the source to 110mA , and the laser housing does not heat much, close to nothing, just a little if you have it a log time switched on.

the datasheet says 150mW @ 165mA, but i will wait up to build a heatsink for the housing to run that current. 110mA = cool ray in the dark (and burns)

[hboy007]

for GaAs type laser diodes, the typical operating current is within 1.5 - 2x of the threshold current. I can't tell you if this also applies to GaN systems but my diode started to show fluctuations in the beam profile before it died after about 10 minutes of continous operation. Mount the diode on a heat sink and observe the fourescence of the unfocussed beam on a paper screen. If you start seeing travelling stripe patterns your diode is at the verge of dying ;)

[CrazyScience]

Put heat sink on the diode - better than sorry. Nice vid anyway.

[hboy007]

after this video I mounted the diode into a massive aluminium block - it died after 10 minutes of continous operation at 85mA.

[phazonxl]

how exactly does one test the current while the diode is running? connect the meter in-line with the diode and power up?

[hboy007]

negative on that

[si12j12]

Very nice, im also running the LD with the 317t ,adjustable minipot, 12ohm resistor ,n4001 and 47uf 16v cap , runs prety well imo.

Are you on LPF?

[hboy007]

Thanks Alfonatr!

I tested the operation temperature before recording this video. For such a short time, everything is fine below 100mA. Did your diode arrive?

[Alfonatr]

Make sure to cooling the diode,, but is great ^_^ , I'm waiting for a same diode from ebay.