Laser pico projector for making color holograms

Holography related topics.
soda
Posts: 38
Joined: Mon Oct 08, 2018 4:05 am

Re: Laser pico projector for making color holograms

Post by soda »

The pico engine was modified heavily: Red and Blue diode was removed and turned 90deg to have same polarisation as Green. Added TEC, thermistor and shutters. Created specialized quad high stable, low noise drivers for laser diodes and PPLN heater, an Arduino based TEC and shutter controllers. Exact wavelenghts are 449.1, 528.4 and 640.7nm. Created FPSI and tuned the diodes and OPSL to SLM. Later I will add monitor photodiodes to monitor noise...
Attachments
021120181173.jpg
021120181173.jpg (780.78 KiB) Viewed 59802 times
pico.jpg
pico.jpg (95.09 KiB) Viewed 59802 times
John Klayer
Posts: 273
Joined: Thu Jan 08, 2015 2:28 am

Re: Laser pico projector for making color holograms

Post by John Klayer »

Looks good!
What are the actuating mechanisms of the shutters? What Voltages are you using for the green laser and the heater? I'm having some problems getting my green going. What temperature are you setting with the Peltier?
Thanks
soda
Posts: 38
Joined: Mon Oct 08, 2018 4:05 am

Re: Laser pico projector for making color holograms

Post by soda »

The shutter actuators are made from relays :-)) with soldered Cu foil arms which block the beams. The green OPSL module needs current drivers, I use 406.5 mA for the IR diode and 81mA for PPLN heater, which is really sensitive. I need to set temperature around 22C, due to the red diode at low temperatures is multimode. Note the prism, which reflect sample beam to FPSI - unfortuntely needs to be tuned constantly. The green OPSL wants to be cooler and red warmer to stay single mode and diodes are really sensitive to backreflections from spatial filter and FPSI...
Attachments
First test on my SilverX plate
First test on my SilverX plate
ChMaRGB.jpg (98.46 KiB) Viewed 59780 times
Kristiaan Meerlo
Posts: 19
Joined: Sun Sep 27, 2015 9:01 am

Re: Laser pico projector for making color holograms

Post by Kristiaan Meerlo »

The first color hologram made with the pico projector. Very good job. My hololab is nearly finished then i try also some experiments with it. I have a ultra lownoise diode and Tec controller from ILX lightwave I am going to use that one to control the red diode.
I have also a Tec and diode controller from Wler I will use that for the blue diode.
holomaker
Posts: 772
Joined: Wed Jan 07, 2015 8:01 am

Re: Laser pico projector for making color holograms

Post by holomaker »

excellent work soda! can you provide details of the hologram? film, how far away was your pinhole from the projector..... i Gave up on trying to use the housing and removed all three lasers.....
soda
Posts: 38
Joined: Mon Oct 08, 2018 4:05 am

Re: Laser pico projector for making color holograms

Post by soda »

Holoplate 9x12cm is my own "SilverX" emulsion, evolved from Silver Cross project. Developed CW-C2 2min, Brilland bleach. Unfortunatelly on screen looks better than in reality, due to small blue shift, the blue is barelly visible by eye. Also beam alighment is not perfect, note too much green left down corner. I'm thinking hard about ECDL version of the pico... Current version have too much compromises, disabling higer power settings. Distance projector to spatial filter is roughly 1m and distance filter to plate/object assembly (Denisjuk) is roughly 1.5m.
Attachments
unfortunatelly on screen looks better
unfortunatelly on screen looks better
blackRGB_1s.jpg (174.14 KiB) Viewed 59708 times
holomaker
Posts: 772
Joined: Wed Jan 07, 2015 8:01 am

Re: Laser pico projector for making color holograms

Post by holomaker »

Kevin over at FBHF pushed the PPLN laser to over
125 mW was under 600mA and still maintained SLM
Under 10Mhz line width...... meters of coherence 👌
Joe Farina
Posts: 804
Joined: Wed Jan 07, 2015 2:10 pm

Re: Laser pico projector for making color holograms

Post by Joe Farina »

Wow, that's nice! What a difference color makes. Congratulations on the self-made silver emulsion, that is no easy task.

An ECDL version of the pico projector would be very interesting. I'm guessing that all three lasers have similar nominal power (maybe ~80 to 130mW?). In free running mode, blue might be lagging too far behind. With my material, DCG+MB+R6G, most power is needed in the blue (around 450nm) compared to green and red. I think the same is true for Liti.
holomaker
Posts: 772
Joined: Wed Jan 07, 2015 8:01 am

Re: Laser pico projector for making color holograms

Post by holomaker »

I have a 450 on the bench now set up for ELCD testing shortly....
User avatar
Wler1
Posts: 2
Joined: Sun Apr 28, 2019 11:32 am
Location: Geneva, Switzerland
Contact:

Re: Laser pico projector for making color holograms

Post by Wler1 »

Hello,

I finally managed to have a first look at those neat devices and do some measurements, thanks David for sending a couple. Now the first thing was to kill the red diode of one device. I like to replace it, but it is totally unclear whether it is practically feasible, given the ultra-precise but hardly adjustable press-mount.
So the question is: did anybody succeed replacing the red diode without messing up beam collimation and centering?

An analogous question is about the PL530. As it turns out, they can vary quite a lot in power and spectral purity. On the other hand, the collimation optics of the white light engine is pretty good. However, the PL530 seems pretty tightly pressed into the holder, and it is unclear whether it makes sense to try to replace it with a better one.
So the question is: did anybody succeed with replacing the PL530 while maintaining the excellent collimation?

Thanks for tips!
Wolfgang
Post Reply