Quad 642 / 660

[laser_freak]

I have slowly been learning as much as I can about combining methods and planning my own quad. After days of planning, weeks of waiting for parts to arrive, and hours of aligning I can finally say I have finished my first multi-diode combiner.

It uses:
2 lpc-826 for ~475mW of 660nm
2 HL6385DG for ~250mW of 642nm
1 waveplate in a Thorlabs rotational mount
4 Optima lenses
Overall dimension is 4 x 4.5 inches

90% of the components are from Dave. He is awesome.

The most difficult and unexpected challenge was the near-field alignment. Oddly the beams weren't all at the same hight so I used varying layers of kapton tape to compensate.

I will try to get some beam size measurements and divergence calculations done tonight.

[andy_con]

nylon screws holding the brass diode holders down = not good

you will get movement

[laser_freak]

Yes, I had read that before but so far no movement even after multiple temp cycles. I will continue testing and switch to metal screws + insulating sleeves if it starts moving.

[catalanjo]

Intriguing ... is the second driver just a spare ?

Also I have used Dave's mounts upside down with nylon posts and peltier under the block and had no movement problems either. (more relevant in blue .....I spose)

Eagerly awaiting power/beam specs etc

Cheers

[swamidog]

the second driver is necessary as the two different diode types have different electrical characteristics.

Intriguing ... is the second driver just a spare ?

Also I have used Dave's mounts upside down with nylon posts and peltier under the block and had no movement problems either. (more relevant in blue .....I spose)

Eagerly awaiting power/beam specs etc

Cheers

[catalanjo]

Oops!.....

Cheers

[laser_freak]

The power stated is the actual output power, not the raw diode power. 725mW after the PBS cube. I'm waiting for it to get dark so I can bring it outside and get pictures of the beam and long distance size measurements.

Thanks for the suggestion catalanjo, I had never thought of using dave's mounts upside down. I may switch to my other set of dave's mounts which have a thermistor in the diode mount and a TEC epoxied between the diode mount and the mounting plate. That would allow me to use metal screws, but I would probably still need to use the kapton tape for near-field alignment.

[dnar]

I have slowly been learning as much as I can about combining methods and planning my own quad. After days of planning, weeks of waiting for parts to arrive, and hours of aligning I can finally say I have finished my first multi-diode combiner.

It uses:
2 lpc-826 for ~475mW of 660nm
2 HL6385DG for ~250mW of 642nm
1 waveplate in a Thorlabs rotational mount
4 Optima lenses
Overall dimension is 4 x 4.5 inches

90% of the components are from Dave. He is awesome.

The most difficult and unexpected challenge was the near-field alignment. Oddly the beams weren't all at the same hight so I used varying layers of kapton tape to compensate.

I will try to get some beam size measurements and divergence calculations done tonight.

Awesome. I too found the brass mounts hard to set near field. For me I had 2 pairs dead horizontal, the other 2 had a slight uphill attitude so I placed tape under the back side of the mounts.

Twiddlies would be great.

[laser_freak]

Twiddlies?

I calculated the divergence to be 1.1 mRad x 0.3 mRad. I have an idea to reduce the x-axis divergence to match the y-axis divergence, but I don't want to spend another 5 hours aligning it.

I forgot to get pictures of the beam profile. Tomorrow.

[catalanjo]

Twiddlies?

Yeah... what on earth are twiddlies?

I have a vague feeling that they might not have very good thermal conductivity !

Cheers