2.5 - 3W RGB Mix Help for Graphics Only Projector

[lasershowsimon]

I want to use an RGB DPSS source instead of a gas white light 3 phase laser in an existing 2 scan set projector - the 3 Phase white light is not an option. This output of the mix needs to be approx 2.5 - 3W and will be modulated with existing PCAOMs inside the projector, 1 for each scan pair. I do want to retain the PCAOMs for colour control and I am asking for advice for the three best DPSS source RGB lasers for the job.
If I were to purchase from CNI, can anybody recommend the power mix and which lasers to look at - I am confused with so many variations of DPSS lasers they manufacture and the quality of the beam etc. I would also prefer the 457 blue over the 471 but again I need advice about beam quality over power etc especially with the routing through the PCAOMs. The projector is for graphic shows only and will never be used for beam shows. I really would appreciate anybody's suggestions about which DPSS modules to use and a good white mix for approx 2.5 to 3W max.
Thanks Simon.

[polishedball]

What size projection area or throw distance? curious

I want to use an RGB DPSS source instead of a gas white light 3 phase laser in an existing 2 scan set projector - the 3 Phase white light is not an option. This output of the mix needs to be approx 2.5 - 3W and will be modulated with existing PCAOMs inside the projector, 1 for each scan pair. I do want to retain the PCAOMs for colour control and I am asking for advice for the three best DPSS source RGB lasers for the job.
If I were to purchase from CNI, can anybody recommend the power mix and which lasers to look at - I am confused with so many variations of DPSS lasers they manufacture and the quality of the beam etc. I would also prefer the 457 blue over the 471 but again I need advice about beam quality over power etc especially with the routing through the PCAOMs. The projector is for graphic shows only and will never be used for beam shows. I really would appreciate anybody's suggestions about which DPSS modules to use and a good white mix for approx 2.5 to 3W max.
Thanks Simon.

[lasershowsimon]

What size projection area or throw distance? curious

It will vary depending on venue, anything from 10m to 60m, but initially only approx 10m.

[Dr Laser]

I want to use an RGB DPSS source instead of a gas white light 3 phase laser in an existing 2 scan set projector - the 3 Phase white light is not an option. This output of the mix needs to be approx 2.5 - 3W and will be modulated with existing PCAOMs inside the projector, 1 for each scan pair. I do want to retain the PCAOMs for colour control and I am asking for advice for the three best DPSS source RGB lasers for the job.
If I were to purchase from CNI, can anybody recommend the power mix and which lasers to look at - I am confused with so many variations of DPSS lasers they manufacture and the quality of the beam etc. I would also prefer the 457 blue over the 471 but again I need advice about beam quality over power etc especially with the routing through the PCAOMs. The projector is for graphic shows only and will never be used for beam shows. I really would appreciate anybody's suggestions about which DPSS modules to use and a good white mix for approx 2.5 to 3W max.
Thanks Simon.

There is a program Chroma Tocket did. It calculates power and white balance very well.

[loopee]

This output of the mix needs to be approx 2.5 - 3W and will be modulated with existing PCAOMs inside the projector

Hey Simon


From my understanding of PCAOM’s (and anyone please correct me if I’m wrong) is that you need lasers that are polarised in one direction for them to work properly something that most high wattage DPSS lasers aren’t (especially in the stacked 635nm diode types)

The other issue you will have is beam size; a high wattage gas laser will have a small beam size where as a mix of DPSS lasers won’t especially if you using 635nm lasers.

Why not just use two lot of 1.5Watts RGB, one for each scan pair and use the built in analogue modulation by passing the PCAOM’s? (sell the PCAOM to recover the cost of the laser modules)

Your best bet is to use 640nm, 445nm with 532nm to keep the size down and at that power it won’t be cheap (CNI also don’t do any high powered 640 or 445 lasers)

Do a search on the forum as there have been discussions on this before

Also, speak to Dave as they are starting to sell some high powered stuff


Troy

[Insanity]

I built a projector aroud 2.5 watts which does lovely graphics... See: http://www.photonlexicon.com/forums/...hlight=monster

The green in it is due to be replaced with a Laserwave 1 watter when it arrives, because it is a Lasever and as such, unreliable with a horrible beam... But once replaced this will be an almost perfect projector... All of the lasers in it are polarised and as such should work with a PCAOM, though I am unsure if the beams just need to be polarised or polarised in the same direction to use the PCAOM...

Anyhow, all the beams match nicely in profile with the exception of the Lasever green, so there are no red outlines around the graphics and it has two blue wavelengths which opens up the colour pallette no end...

Power and wavelengths are as follows:

Kvant 600mw @ 640nm - Actual power = 650mw
Lasever 600mw @ 532nm - Actual power = 850mw when it feels like it, soon to be replaced with a 1 watt laserwave.
CNI 200mw @ 473nm - Actual power = 300mw
Kvant 500mw @ 445nm - Actual power = 480mw

Hope that helps
Mark

Edit: the colour spill in the pics is due to my crappy camera and not the projector itself

[Jem]

All of the lasers in it are polarised and as such should work with a PCAOM, though I am unsure if the beams just need to be polarised or polarised in the same direction to use the PCAOM...

Hi Mark

I think the lasers need to be polarised in the same direction to get the best out of a PCAOM. However, it isn't such a problem if your lasers are polarised in different directions as you can either mount the lasers on their sides, or a more elegant solution would be to use a halfwave plate in front of each laser, you can then set the polarisation to any angle you desire.

Jem

[Insanity]

Cheers Jem,

That makes perfect sense. I have used them with gas lasers in the past, but never seen the need on solid state as I normally do beam shows and I guess colour fading etc is not so important as it would be with graphics, plus PCAOM's introduce their own losses and beam shows are more about power, so I stick with Analog modulation. Simpler, cheaper and effective enough for what I do...

The only thing for me to add to my previous post based on this is that I mix the blue's in my projector through a PBS and you would have to mix them with a Semrok or similar dichro instead if you are using a PCAOM..

Mark

Hi Mark

I think the lasers need to be polarised in the same direction to get the best out of a PCAOM. However, it isn't such a problem if your lasers are polarised in different directions as you can either mount the lasers on their sides, or a more elegant solution would be to use a halfwave plate in front of each laser, you can then set the polarisation to any angle you desire.

Jem

[lasershowsimon]

Thanks so far for all the information guys. It is interesting to see all the feedback regarding using modulated lasers instead of the PCAOMs. In my build that I have at the moment that just uses 2 RGB projectors from China, they have analogue modulated lasers in each, but as far as I can see they are only around the 10Khz mark. I had an early projector when I was in the UK that had a Laser Physics Reliant white light in her, and used an 8ch PCAOM for colour control which was awesome and managed graphics such as the LINEA show from the LD2000 free shows to run perfectly. Is the reason that playing back this show is a no-starter now with my current projector because of the slow analogue modulated diodes? This was one reason to stick to using the PCAOMs in this new 2 scan projector as this was how originally the white light gas laser was colour controlled, it would mean completely changing the whole optical path inside the projector as the waste beams from the PCAOMs were used for other optical effects. This is the main reason I wanted to use one input beam hence wanting to get some advice for the best DPSS diodes to use in this way, good beam quality, good colour balance at around the 2w mark. I can see the advantage to using the 2 blues over the one, I was always less keen on the 473 blue anyhow as it just doesn't have that beautiful deep blue that I used to get from my Reliant. Anyway, I am slowly learning more and more from you guys which is great as it will be a challenge to get this projector up and running so the more help I get from everyone the better - What is the best RED for beam quality over brightness as I said before, it is not for beam shows and I always get so lost with the differences in the quality of the REDs, is the 671 the best red to look at? Again, any help would be appreciated.

[Insanity]

The 473nm Blue gives nice cyan colours when mixed with a bit of green, but like you say, it doesn't manage the deep blues and violets so well. I have also noticed that a lot of 473's have a TEM01 beam and I think (not an expert on this subject by any means) that most DPSS lasers are limited to 10khz modulation. I also notice that they are very sensitive to temperature and in a cold venue can take a long time to get up to power and become stable.

The 445nm on the other hand gives the very deep blues and violets. It is a direct diode laser which I believe modulate faster than DPSS (again I could be wrong). These lasers also get up to power very rapidly, but the beam is not round, more of a stripe, but if you use a watt of 445nm it has two diode's and the stripe becomes a cross which with good optics in the laser module itself becomes hardly noticable. This may or may not affect polarisation depending where you buy it from.

As for reds, this is what I have found:

650nm and 635nm lasers tend to have very fat beams in comparison with other lasers, particularly DPSS. Most 635nm lasers have awful divergence.



I am using 640nm which again is a direct diode, mine has 4 diodes in it, so at aperture you can see 4 very tiny beams which are cleverly collimated to blend into 1 beam after about 1Mtr. The resultant beam is very tight with a good divergence ~0.8MRad. The other thing I have noticed is that 640nm gives a surprisingly deep cherry red as opposed to the more orangy colour of the 635nm.



671nm lasers are DPSS and have very nice TEM00 beams, but 671nm is a very deep red, so you need huge amounts of it and things start to get expensive. A combination of 640nm and 671nm would give a nice extension to your colour pallette.

I am no scientist by any means, but this is what I have found through building various projectors over the years. I am sure the more scientifically minded people in the forum will jump in and explain all this better than me...

Mark