My Dual 445 Build

[laserkits]

Just wanted to share my progress on this project with everyone. The current 445 that's installed in my RGB Build (a DHOM 600 mw) just has such a bad beam quality compared to my DPSS Green and the LaserWave 640 Red, that I have been conspiring to replace it with a home brew for some time. I have been collecting components to do this build for quite a while now and decided to get started on it this week... Came up with a design layout and drew it up in AutoCAD on Monday afternoon. Ran down to the shop after work and milled all of the aluminum Monday evening. Tuesday evening I assembled the diode stacks, mounted the Dielectric Mirror, the PBX Cube, both flexture mounts and the Wave Plate. By the end of a looooong evening I had it all optically aligned and kicking serious butt. The only thing that remained was the addition of the Anamorphic Prism Pair that I finished last night. I am very pleased with the quality of the beam after the corrective optics. The alignment of the prisms was actually the most difficult process of this build and you have to do a lot of testing and planning to get everything in the correct location, beam exit where you want it, beam exit perpendicular to case, etc...

Here are the Specs:
2ea Casio 445 Diodes from Fleabay
2ea 405G-2 Lenses and adjustable housings from laser66.com
445 AR coated PBS Cube
445 AR coated Wave Plate
Dielectric 10mm mirror for 445
445 AR coated Anamorphic Prism Pair
All of the 445 optics are from Rob at Stanwax
Balance of parts machined in my shop

Output: Its making 1.4 Watts @ 1 amp

Beam: Outstanding for a 445. I'm really pleased with the fact that it appears to even better than my LaserWave 640. Measures 5mm x 8mm at 33 Feet (10 Meters)

Losses: Losses are quite high in this setup. Measured losses of 35 % through the Prism Pair alone... Add that with losses from the Beam merging at the PBX Cube and we are close to 50%. However, since 445 is cheap, I'm very happy with the power I'm getting with a nice corrected beam.

Next I will get the cover milled and ready for the TEC installation this weekend. TEC should be here tomorrow. TEC will sandwitch between the top of the diode mounting black and the cover assembly. Cover will have milled fins and 12v fan.

Driving the two diodes in Series, using a Flexmod P3.

Still deciding if I will use a feedback circuit to monitor the temp of the diode block with a type-K thermocouple. I was thinking of using an op-amp circuit to monitor the thermocouple and drive the input of a second Flexmod to power the TEC. Has anyone tried this?

Thanks Guys... More to come.

Rob

[andy_con]

looks very nice and clearn. all you need now is a lid to seal it

[LaNeK779]

wow! impressive build!!

just a question about the waveplate. how is it attached there? glued? so first you rotated it until you got the best output and then you glued it in place?

i would advise against the flexmod driving the tec, as i see no point. a simple dc psu would do, when combined with your thermocouple - opamp circuit

[allthatwhichis]

Nice build man; I am curious though... Why do you have a wave plate? I would think a + beam would be better than a = when only using two diodes...

[taggalucci]

Perhaps because a = will work through a prism pair whereas a + won't.

[andy_con]

you can use a prism pair with + both beams need to be =

[laserkits]

wow! impressive build!!

just a question about the waveplate. how is it attached there? glued? so first you rotated it until you got the best output and then you glued it in place?

i would advise against the flexmod driving the tec, as i see no point. a simple dc psu would do, when combined with your thermocouple - opamp circuit

Yes the wave plate is glued. I use Rear View Mirror Adhesive to attach all of my optics. It uses an activator on one surface and a clear adhesive on the second. Once you press them together you have a rock hard bond in seconds. You have to be very careful to get things where you want them because there are no second chances... Yes I held the wave plate between my fingers and rotated it using my LPM to get the most throughput. I then marked the area where I wanted the adhesive. After a small dab of adhesive and activator on the opposite surfaces, I brought it back into position and again using the LPM rotated it for best output then simply reached in with a pop-sickle stick and pressed the joint together. 2 seconds later, you have a perfect bond... Thanks for the info regarding the flexmod. Think I will just use a mosfet to turn the power on/off to the TEC using an NTC as a sensor...

Rob

[laserkits]

Nice build man; I am curious though... Why do you have a wave plate? I would think a + beam would be better than a = when only using two diodes...

In order to combine the beams through the PBX without the wave plate the beams would have to be like "+" instead of "l" due to one being turned 90 degrees as you pointed out. The whole purpose of the PBX is to get "l" and not "ll" as you would with stacking. To make use of the Anamorphic Prism Pair which only affects the beam in one axis, we need both diodes in the same orientation so the prisms can correct the Fast Axis of the Diode... I am getting a fantastic beam out of this. I compared it last night with my DPSS 532 from DHOM. At 40 feet the green is 15mm diameter. My 445 is only 10mm in diameter at the same distance and it is very close to a perfectly round profile. Its actually better than my Laserwave 640. I will try to get some beam comparison shots...

Cheers,

Rob