Designing an easy to manufacture AOM mount

[robotarmy]

Hey all!

I need a Bragg mount for my AOM, and i'm broke as hell so I can't buy anything fancy. I have access to a fairly well-stocked machine shop, and was wondering what adjustments are the MOST essential to proper tuning of an AOM?

Obviously it's most important to have the ability to adjust the angle of the crystal rel. beam axis.

If i wanted to add another degree of freedom what would the next best thing be? Translation along the length of the AOM crystal (to find the sweet-spot near the piezo driver?), rotation around the beam axis (to find the real direction of polarization?), or something else that i'm missing completely?

Thanks!

[mixedgas]

Yoda say, Rocket Science, is this not. I can make everything I need for most AOs with a drill press and a hack saw.
PCOAMs need a bit more precise mount.

In order of operations:

1. rotation about the marked axis on the bottom of the cell. Often there is a hole for a pin in the AO bottom.

If I add anything, its:

2. Translation left right
3. translation up/down
4. Tip/tilt. (if you want that last 2-3% of your power, but rarely needed, helps beaucoup with with PCAOMS, can buy you 6-7 percent more power with some PCAOMS)

Rotation for POL is NOT needed.

I usually just take 2 pieces of 1/4" thick aluminum stock one inch wide, cut them a few inches long, and drill holes for the AOM in the top one, plus a friction fit hole for a piece of drill rod either 1/8" diameter or 1/4" diameter precision shaft, aka drill rod. I then press a instrument sized ball bearing in the bottom piece. I then bolt on on a 1/4-80 screw or a cheap 1/4" travel micrometer (Shows up a lot in surplus medical gear) to the bottom one on a small tab. The micrometer or ball tipped screw presses on a rod or piece of flat stock screwed to the top piece, and a spring pulls the top piece back towards the adjustment device (This is overkill, a 32 pitch or 40 pitch screw works well enough for the patient). The spring is fixed to the bottom one.

I usually use hardware store 1" wide 6061 bar stock, and I dont even flycut or mill it. Its non-critical.

The above assembly goes on a standard half inch optical post in a post holder, on a slotted sliding foot. Thorlabs usually sells the post holder, post, and sliding base cheaper then I can mill/lathe them.

The sliding base is usually enough for the left right adjustment, and posts work for the vertical for most lasers.

Example for tip/tilt, if you wish to spend a few hours on UN_NEEDED MASSIVE OVERKILL, would be a Thorlabs KM100B

Other Parts I would use

BA1S
PH1.5
RA90
TR1.5

More modern AOs just use the centering pivot pin and have flange with curved slots in it. They align them by hand and bolt em down using the slots. Often its that non-critical.

You can usually learn all you need about normal AOs (ie less then 2 watts drive, which is 85% of whats out there) by holding them in the beam and setting up a half hertz blink in software or on a signal generator.

Usually very non critical


Tip, if your laser is too fat in diameter for your AO, focus it down and then recolimate it with a pair of identical single element lenses, or cheat and drill out the hole.

NOTE< most AO cells have a pair of hair thin or smaller gold bond wires, be careful if you open the AO up.

20 minutes with the drill press and 10$ worth of materials usually does it for a basic mount.

Steve




Steve

[robotarmy]

Ahh beautiful! Exactly what i was hoping. Thanks Steve! (did you get my PM btw? i need to rebuild that PSU and i just got tony aztec's setup as well... another alc68+meditech... i'm hooked, shit.)

[robotarmy]

Like that?