Future of portable BLUE

[Milos]

Will BLUE 473nm DPSS lasers come in higher power as 808nm pump diode become more powerful and affordable, or is there a big crystal issue limiting it as well?

Lets say tomorrow we get 5W+ pump diodes at low prices. Will that mean 473nm hand held lasers will easily reach 100-200mW?
Will current crystal sets in portable blues be sufficient to handle these higher powered diode,s or the whole new cavity will be necessary ?

 

[LarryQ]

Re: Future power of portable BLUE

I was always under the Impression that it was the Crystal that was the problem.

Due to the Chemical makeup , and the difficulty growing these crystals...

I would not be suprised at all if High power 473nm DIODES actually made it on scene first!

Laser TV and It's potential as a Huge Money Maker will provide the research funding for truly Blue diodes!

I'll wager that we will look back at the DPSS Blues as a Novelty!!

Larry

 

[Milos]

Re: Future power of portable BLUE

That would be very nice if it happened in next year or two. I hope I'm wrong, but I doubt so.

Does anyone know how much power per color laser TV requires?
I'm curious if its in hundreds of milliwats or possibly few Wats.

I still see DPSS blues in next year or two growing in power, but I'm curious weather they can grow much more than they are now while keeping the small size.

 

[Benm]

With current technology, output power of dpss blue will be rather limited. Larger pump diodes can't do -that- much for them. The problem is not accepting the 808 nm pump light, but the lasing in the solid state laser at 946 nm, which is a minor line for the material used. You can only pump so much energy into a crystal before it just overheats and breaks apart.

Does anyone know how much power per color laser TV requires?
I'm curious if its in hundreds of milliwats or possibly few Wats.

That depends very much on how large you wanted that TV, and how dark the environment you watch in is. Brightness is just a factor of optical output, it makes little difference if this comes from a laser or a HID lamp as used in current projectors.

Just as a ballpark figure, a typical home projector would use a lightsource of at least 100 watts. Given 5% efficiency (HID with filter losses) that would equate to 5 watts of total laser ouput.

 

[philguy]

I think that depends. Intuition tells me that a projector (across the room) will need more power than an enclosed back-projection-system, but then again I might be wrong.

Also, considering the history of lasers, I think nothing is really certain. You might have a discovery in the next years that compares to the jump from gas tube to diode lasers. Alternatively, a "bluer" diode might get developed, or higher-powered diodes might appear.

But whil I was shining my 30mW (which isn't even top-notch pen-sized power), it occured to me that had you told a scientist ten, maybe five years ago, that soon frequency-doubled lasers would be available in (comparatively) high powers for cheap prices, he would have a hard time believing it. I still have a hard time believing that I can get 250mW of red power for 16$, although I got one in my hands, lasing happily along. Several Weeks ago, the idea of having a 250mW laser would have thrilled me, but I would have put it off as "expensive unrealistic idea".

Now, apply that to blue lasers. Maybe a press release is being shaped right now, or an article is waiting to be released into the internet describing the development of a cheap high-power blue laser system. Maybe in two, three years from now we will look back and say "had we known...", while we play with our RGB/frequency tunable portables. Maybe not even DPSS or "conventional lasing", but some other exotic way of creating coherent monochromatic light, that is just "duh!" simple, nobody just noticed yet

But then again, it could be that the industry is "stuck" on this level for another two decades!


To sum it up, I also think that DPSS will increase in power, possible frequencies while decreasing in price. Still, whether any great leaps in technology will be part of this is doubtful. But I am curious as to what the future brings.

 

[philguy]

that would equate to 5 watts of total laser ouput.

Question is if the fact that the laser dot is focused to such a high-intensity spot will require higher or lower power rates compared to conventional lighting.

 

[Milos]

With current technology, output power of dpss blue will be rather limited. Larger pump diodes can't do -that- much for them. The problem is not accepting the 808 nm pump light, but the lasing in the solid state laser at 946 nm, which is a minor line for the material used. You can only pump so much energy into a crystal before it just overheats and breaks apart.

ok, wahat about lab DPSS blue lasers. They can be purchased at higher powers because of more powerful pump diodes as well as - and here comes part of my point: higher quality expensive crystals or simply bigger crystals with more powerful pump? Those lasers can reach hundreds of milliwats.

That depends very much on how large you wanted that TV, and how dark the environment you watch in is. Brightness is just a factor of optical output, it makes little difference if this comes from a laser or a HID lamp as used in current projectors.
Just as a ballpark figure, a typical home projector would use a lightsource of at least 100 watts. Given 5% efficiency (HID with filter losses) that would equate to 5 watts of total laser ouput.

I would agree with Philguy that projectors project light across the room and Laser TVs simply send coherent light to display screen. That being said, I think Laser TVs use a lot less power than a projector lamp. Its only my guess though.

Does anyone know about this Blue DIODE lasers. Is this DPSS ?
http://cgi.ebay.com/Laserworld-BLUE...ryZ53141QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

 

[philguy]

I think blue lasers in that form factor only exist as DPSS.

Still, it appears that $18k is expensive for a 1W laser (even for expensive blue dpss).

 

[pseudonomen137]

In the mW range, you pretty much only have 473nm DPSS to work with if you have any sense of budget. As BenM said, the problem is that although its DPSS similar to a 532nm process, its inherently much more inefficient.

473nm units do exist in high powers, hundreds of mWs and even into the Watt range. However, just like with high power green lasers you run into two problems with portables - power and heatsinking. If you have a Herc-form blue, sure you could probably get in the 100mW range (and it would cost a crap load!). When you have things like the RPL blue and all though, you're severly limited by both problems. The RPL blue 20mW units use the same pump as the RPL green 300mW, but the 473nm process is just that inefficient. There are 5W+ pump diodes and 473nm DPSS crystals for that power, but a body like the RPL simply can't handle that much power/heat.

Summary: Yes, the diodes and crystals already exist to make higher power 473nm units, just as diode arrays/crystals exist to make hundred watt+ green lasers. Because of two key issues though - heatsinking and battery life - both DPSS processes are very limited as to what you can make portable.

 

[ixfd64]

I think that it's definitely possible that portable blue laser swill go tino the >100 mW range. Some time ago, Jack from Optotronics showed us a video in which an "RPL-30" peaked at close to 80 mW.

By the way, the price for the RPL-30 has been reduced to $1,199. I have a feeling that Optotronics will sell more powerful lasers in the RPL series soon.

 

[Benm]

Question is if the fact that the laser dot is focused to such a high-intensity spot will require higher or lower power rates compared to conventional lighting.

The answer to that would be rather simple: If you scan a laser over a surface like in a projected TV screen, it is no longer a dot. In a projector, the typical output 'beam' is in the order of 1 rad divergence (a 1 m screen at 1 m distance). It does not matter what you use to light that surface, its all about optical power ouput.

Laser projection would be superior when projecting small screens at large distances, since lamps are not point sources, they cannot be collimated well enough to make a projection of say 1 meter wide at 50 metres distance. A good laser can do this with decent resolution.

There is one different situation though: with a laser you can scan an image and skip the black parts, so drawing a circle (or any other outline) will work much much better using a laser scanner.

 

[philguy]

that's what I meant where I wasn't sure - a 1W green dot would have to be fairly bright and leave quite some aftertail in your vision, but if scanned with 85Hz/60kHz, this might not be the case. But you see, I don't have a 1W green raster scanning laser system in my living room to try this, so nonreliable info from me here.


Anothet thought that came to me was that I once read about coherent microwave/RF sources, that if you have 100 coherent emitters and 100 non-coherent emitters focused on one spot, the coherent dot will have the hundredfold intensity than the incoherent dot. So maybe this plays some role, too, as a laser is basically many coherent sources combined, and the eye sees intensity and not amplitude (afaik). Or, in other words, a 30mW laser appears way brighter than a 30mW diode the same colour.

 

[Greenie]

All I have to say is give it time.

 

[Rhith]

Who knows I might even be one of the people to work on developing this! (BTW I plan to get an AAS and Masters in the Photonics field.)

 

[darklandz]

y cant they just sort out the heatsink problem for blue portables, imagine holding an rpl blue 300 man that would be the most awesome thing on earth!!

 

[pseudonomen137]

Well, the problem is mostly waiting for some laser manufacturer deems it worthwhile to design the heatsinking for a more powerful blue. Its not any shortcoming in pump diodes, crystals, photonics, etc - its not really a laser issue at all. 473nm lab lasers in hundreds of mWs, if not Watts, are already commonplace for those with the pocketbook. Just like with a greenie though, you have limits to what the raw materials of a portable form factor can do, and because of the nature of 473nm DPSS, these limits are inevitably a lot lower than 532nm.


Basically what I'm saying is that the day you see a 300mW 473nm portable will be the day you see a 3,000mW 532nm portable. Don't expect that to come in a pen-size unit  


On the other hand, if those 440nm blue diodes start becoming more powerful and commonplace...