Night photo 700mw BDR S06J-12x-405nm Blu-Ray Laser Pointer

[AngelG]

Re: Night shot of my 700+ mw 405nm Blu-Ray Laser Pointer

...............
Also, I've said this before but repeating it, IR diodes are difficult to focus for a distance because you can't see anything, ........

Well, I will share my method for focusing. It may or might not work for you.
I calculate a resistor for the LD to operate slightly above it's threshold current (we're not going to burn the sensor). Then I solder a simple switch made of 2N2222 transistor and 2 resistors so it could be PWM controlled by let say STM32 MCU.
I run it at 0.05% duty cycle with F>1 kHz.
Next, I remove the lens and the IR filter (if any) of my CMOS web camera to reveal the bare sensor. Most of them are sensitive enough to "see" the IR beam.
Then I mercilessly point the spot onto the sensor's surface.
0.01mW won't destroy it, I believe.
I watch the spot on the monitor. On 1.3 Mpix sensor the spot is pretty big, so I can focus quite well...
Do you find this easier ?

Btw nice beam. Got inspired and ordered S06J diode on ebay. It look like it's Nichia.

 

[Alaskan]

Old thread, but same topic.

I'm interesting in how much you paid for the diode? That one is not the higher power "16X" 405n single mode diode some push to nearly 900mw output, but it is fairly powerful.

Since this post, I found a way to focus an IR beam to infinity; just use a video camera which can detect the wavelength and shoot the beam from the laser through a PCX cylinder lens while watching with the camera, then focus the collimating lens on the laser until the line produced by the PCX lens is as fine as you can make it at a far distance, the further the better. After doing so, the beam is well focused to infinity, also, once the beam is at infinity focus, moving the PCX lens closer or further away from the laser does not cause the line to change focus.

This will work at any wavelength.

 

[AngelG]

"I'm interesting in how much you paid for the diode?" - It was not sth. I'm proud with - I won it at the half of the list price ~ 13USD so I hope the seller doesn't suffer a big loss. You know, it'd be not healthy the sources to disappear.
It's in-transit. But from the other people's pix, I judged that it's not Sony but Nichia.
I know it's not the other hnk (unknown) diode alleged to be 900mW, but for the price, this one is O.K. This one is with 5.6mm base, while the hnk BDR209 is 3.8mm - much harder to work with, because of the small size. Since I'm building a new 10-20 MHz modulator, I'd like first to test it on the cheaper one. The simulation results show 5-6 mA overshoot for 20-30nS at 200 mA drive, which I think is O.K. - it will survive.
I suspect that this diode could be NDV4B16 - a 300 mW CW rated single-mode, but I don't have enough evidence. Based on the NDV4B16 datasheet and one of the Sony datasheets, I rate it 300mW / 230 mA CW, 450 mW / 320 mA pulsed (for pulses longer than 30nS, but shorter than 1mS, 50% duty) and 600 mW / 410 mA pulsed - for pulses shorter than 50nS (actually 30nS w/o overestimate).
I also desire power :evil: so the hnk BDR209 will be tried also. For my project, It's matter of rendering time, so the higher power - the better. Talking about LASER beam, I wonder which is the right lens just like the guy in this thread: What lens setup for smallest dot around 300mm distance

 

[Alaskan]

Wish I could help in the best lens question for the smallest spot possible at 300mm, but all of my research has been in low divergence infinity focus lens technology.

 

[GSS]

Whoop's, just got caught up on the first part
Iye let me delete it but you got the jist!!

 

[Alaskan]

I want to set up a voluntary member vetting process, not part of the forum, but between us. Ebay would be a good way to get vetted, if you had an account, or perhaps some other way. AngelG are you up for that? Want to be vetted?

 

[AngelG]

For the people who read the above - we did this vetting and it semi-worked, but it turned out that it is unreliable.
Nobody would like to post his real pic for a more reliable vetting process.
@Alaskan: The white sock was funny