Holographyforum.org / holowiki.org

Thought I would discuss the tuning of the G-75 laser
With only passive cooling these lasers will run SLM !
The tuning curve looks something like the diagram below.

The green represents the lasers mW output

The red represents the lasers heater temperature

the way I finely got it tunes is tuning the bottom pot, till I find a high point (very fine tuning) and that it says stable, then take a microscope side in beam and shoot it past laser on to the wall, look for stable dark fringes, I had to ooo so fine back of my adjustment till I saw stable fringes, then let it run for a bit and see it stays, then turn off then on again let it warmup 15 mins see if its still stable, mine is doing 70mw single frequency,

here is my test of David's laser https://youtu.be/PkSi7oiuy4w

the adjustment on the board really is bad so this was my fix .

I have a volt M hook up to see the right voltage that gives me stability and maximum power, the little Led light I got from a $ store it work really well

it looks like this

So you're connecting the 3 Volt batteries and rheostat from the LED assembly to the heater leads, right?

yes

Jiri over at “laser Hacker “ FB page was kind enough
To share some test information he has about these cool little lasers.....I’ll post more as I get the info. Tuning the 530nm OPSL PPLN:
My sample (thanks Dave!) can run 85mW, adequate for holography but no absulutely clean SLM. Nicely clean SLM found 40mW at 21.5C, 520mA and 80mA. The device is really sensitive to PPLN heater current! I need little to improve the driver. The mode structure was analyzed by FPSI, long term stability checked against hyperfine structure of I2 vapour in iodine cell. The device is incredible stable! The iodine fluorescence can be observed for hours - coherence must be very very long.