I second thatOriginally Posted by Bradfo69
Great explanations as always.
Would it be easier to just regulate each diode with its own separate TEC and a thermistor to monitor/control each diodes temp?
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I second that
Great explanations as always.
Would it be easier to just regulate each diode with its own separate TEC and a thermistor to monitor/control each diodes temp?
I think its exciting provided that it brings down the cost of higher powered reds. Two years ago for example, when the Pluto craze hit, the projectors were 1 watt 445 , 1 watt 532 and 480mW of 637. Most felt initially the red was underpowered and inquired about the red being replaced with a 1 watt red and it doubled the cost of the projector.
This technique appears to require a lot of optics and hardware and engineering as well as a lot of space - similar to the special filter technique. So, if in the grand scheme of things making 5 watts of red with this, versus buying 5 watts of red in a module with 32 diodes is cheaper - yes it may be viable. If it's the same or more, then perhaps not.
I do think perhaps the shift is occurring between building and buying since the prices have come down so drastically. I've mentioned it before in other threads. When I got into computers, a few thousand dollar price tag forced me to go to computer shows and buy all the parts and learn to assemble it myself. Now that I can walk into Wal-Mart and spend $299 for a desktop with more power and features than what I used to build, it's like.... why bother? Hell... just buying the operating system is half of that price if I wanted to build my own.
If this gives us multiwatt cheap reds, similar to the blues then its probably still of some interest.
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Just being able to combine lasers in this manner is inherently exciting. Please proceed!
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You are absolutely correct. This will be easier and will open up the possibility to combine more diodes. This is how I will construct the prototype that I describe above with the caveat that I will place a pair of diodes on each TEC stack so that both polarizations will have a diode at each temperature. I am hoping that some of the participants on this forum with the skills can design/construct a multichannel TEC driver to control these stacks. Hoping...?Would it be easier to just regulate each diode with its own separate TEC and a thermistor to monitor/control each diodes temp?
I think its exciting provided that it brings down the cost of higher powered reds.If this is the general consensuses then I do not think this would be worth pursuing. Red laser diodes of all kinds are not expensive. The lowest cost source for projectors of average performance is going to remain China. I don't think discussing the relative merits of these kinds of systems is interesting. This doesn't mean that these systems are not worth having, just that their operation is not interesting.If this gives us multiwatt cheap reds, similar to the blues then its probably still of some interest.
I am not building any more club style laser projectors because the content that I can practically use is impractical to implement on more than 5 projectors. With all the other entertainment options; video, high quality non-coherent beam projectors and LED walls combined with the wide availability of inexpensive CN laser projectors, lasers are becoming a less important part of an entertainment package. One area that has not commonly seen lasers is outdoor displays. There are regulations and maybe that is the real barrier, but projectors in the >50W range have to be very rare if not unheard of and that is interesting to me. Where I see this beam combining technique being used is to produce 10-40W red and similar 10-40W 445/462 modules. This is not trivial, but aside from LS based systems or huge three phase ion systems this probably does not exist. That is really interesting to me.
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Yes. The laser light show show industry, in general, has moved towards more is better where as before it was bigger is better. This, I believe, is driven by new technology and lower price points. Also, it used to be a "NERD" driven field. Now it's a "GEEK" driven field.Something that has occurred to me is whether the enthusiasm for the construction of more powerful and higher quality laser projectors has largely disappeared. Has the availability of inexpensive projectors from China made the construction of a projector anachronistic?
Its very exciting to some. There is something I've noticed about PL since I started visiting here. Most projector builders here are what I would call module-centric. What I mean by that is, people seem to see projectors as a red module, a blue module, a green module, galvos, and some other stuff. This is different from the way I started building lasers in about '95. Back then projectors were viewed as more of a "projector module" if you will. This ,of course, is due to technology. We didnt have powerful diodes yet. What I am getting at here is... unless its in a ready made package *most* probably don't have a use for it.The theme of my video is the application of a practical technique for producing red laser beams of unprecedented brightness. What I'm wondering is if this is exciting or only an interesting optical phenomenon?
That all being said, trust me, there are people that will use your ideas to make extremely powerful reds. They are paying attention, just not posting.
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That is what I am assuming.That all being said, trust me, there are people that will use your ideas to make extremely powerful reds. They are paying attention, just not posting.
I agree and I think that it is these builders that will most quickly move to the turn key CN projectors.Its very exciting to some. There is something I've noticed about PL since I started visiting here. Most projector builders here are what I would call module-centric. What I mean by that is, people seem to see projectors as a red module, a blue module, a green module, galvos, and some other stuff.
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Blasphemy!
No one ever posts pictures on facebook or twitter saying 'man those LED screens were awsome'
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Maybe not, but there have been several laser operators that have claimed on this forum that as the LEDs have grown larger and brighter that their own lasers have struggled to remain impressive! The writing may be on the wall (the LED wall).No one ever posts pictures on facebook or twitter saying 'man those LED screens were awsome'
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"visuals" ie projection mapping, even when no mapping is occurring ie. a normal screen, is what the kids think is hot right now. on a big show it translates to big led walls. This often comes at the price of skipping over the fundamentals of lighting design, that is, highlighting the performance on stage. LED walls will wash out even a sharpy (or 100 sharpys) often due to a non cohesive production. If u mad then go do some plays or musicals, or anything that isn't a dude with a macbook on stage flailing their arms, throwing cake and champagne into the crowd. Lasers are a genre specific effect
Back to the topic at hand. TLDR, more like watch, I know a spectrometer is expensive and special but what I wanna know would be how broad the wavelengths are over the temperature gradient and how they would settle during modulation. Otherwise I guess you could have it constant on with galvo or acousto opto modulation. It is one of those u gotta see it to really believe it things. Ie. does it actually look brighter having multi wavelengths @ same power than them all near the same wavelength for the same given optical power?
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I have a spectrometer and I used it to characterize these diodes prior to installing them. The line width of these multimode diodes is, surprisingly, narrower than the single mode diodes that I had originally intended to use for the experiment. The line width is 1.7nm down to the 30% level from the center line peak. I believe that there is also some structure to this line width and that the wings contain a slightly different wavelength than the bright central stripe. I believe this is what causes a very subtle curvature in the far field line. This is also what might explain the good performance of even the thermally closer (6 degree C) diodes; the central line width is actually even narrower than 1.7nm!
Modulation does not move the far field spot. I have discussed this earlier. Because the second prism negates any angular changes introduced by the first prism then the effect of a modulation, or current dependent, red shift serves only to laterally shift the stripes and that lateral shift is not magnified from the second prism to the far field because the angle does not vary. Therefore, the magnitude of the lateral shift is proportional to the ratio of the current induced red shift/temperature induced blue shift. In the experiment, the delta T of 26C will produce a wavelength shift of 5.7nm the current red shift will red shift the diode by approximately 1.8nm and this will move the near field stripe by approx 30% of its original width. The far field stripe will move the same small amount and at say 10M this amounts to <100urad. The galvo should not be necessary, but the larger the achievable temperature gradient, the better this will get.
The beam does get brighter. You cannot detect that the beam has a greater band width. It looks identical color-wise.
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