RGV or RGB?

[mfo]

Well, due to my hiatus, I haven't been following the white laser hype as closely as I wanted to. I have a few questions for you white laser users out there.

1) What kind of setup do you have, RGV or RGB? (V = 405, B = 445)

2) If you have experience with both, which one makes a better color range?

Thanks!

 

[goninanbl00d]

Although I don't own an RGB or RGV system (and my advice can be seen as talking out of my buttocks), but I can try and give you a few tips anyway.

445 is much brighter than 405, and is also actually blue. It's also extremely close to the human eye's centre for blue sensitivity, so you don't need as much of it to get a good blue balance.

Although not as ideal as 457nm, it's close enough to give a vibrant blue colour, and to give a vibrant gamut when blending with analog modulation.

With violet, blended colours are much more 'dull', and you also need more of it in any case.

445 can be used 1:1 with 532nm, due to it's closeness to the peak of blue sensitivity. If you try to combine a 445 and 532 beam of equal brightness, the 445 will completely wash out the 532nm.

 

[Cyparagon]

I've still got 473, but I plan to add 445 when I get a mount for additional optics.

445 is a much better choice over 405. It is brighter, safer, cheaper, and offers better color. I've heard RGV has a tough time making blue.

 

[KGB_Productions]

RGV sucks and is worthless now that we have the 445 diodes for blue.
RGB with 445 looks way better than 405, but the dark 445 color brings down the brightness VS 473

In my projector I use 473+445 and that seems to have the best color.

 

[ElektroFreak]

I have both 473nm and 445nm and IMO 473nm by itself won't ever make it into a full-color system of mine again. While I like the colors that can be made by combining 473nm and 445nm, using only 473nm for blue in an RGB is not as good as using only 445nm (or a darker blue like 457nm). The impact that deep blues have on the blue/violet/magenta end of the spectrum is huge, with 445nm giving those colors far greater depth. With today's concert/event stages, the brilliant and blue/violet/magenta hues are highly sought after since they match very well with the LED lighting that is becoming more and more commonplace. My newest RGB system design is extremely compact, so only 1 each of red, green, and blue sources will fit.

To recap:

473nm = bad

473+445nm = good

445nm = good

405nm = bad

IMO

 

[GreenBeam]

...
Although not as ideal as 457nm, it's close enough to give a vibrant blue colour, and to give a vibrant gamut when blending with analog modulation.

...

Hi, is it possible to create 457nm with a crystal and IR diode combo, like 532nm ?

 

[Cyparagon]

Yes, 457nm modules are DPSS.

 

[goninanbl00d]

Yes, that's how 457nm is created. It's DPSS, just like 532 and 473nm.

In this case, the 914nm line of the Nd:YVO4 is doubled in a LBO or BBO crystal to produce 457nm blue output.

 

[GreenBeam]

Yes, 457nm modules are DPSS.

Yes, that's how 457nm is created. It's DPSS, just like 532 and 473nm.

In this case, the 914nm line of the Nd:YVO4 is doubled in a LBO or BBO crystal to produce 457nm blue output.

Thanks - that's what I thought...

This one manufacturer has these, listed below,
I'll ask if they have 914nm too, as new products, not yet listed.

405nm
455nm
635nm
650nm
785nm
792nm
808nm
830nm
850nm
880nm
940nm
980nm
1064nm
1310nm
1450nm
1470nm
1550nm


What's the calculation (if any) that tells the nm out for what goes in?
(is it as simple as wavelength in divided by 2 for wavelength out & desired out x 2 = IR wavelength in) ?

Who sells the crystals, and I also guess each crystal does something different to the IR in,
for the desired wavelength out?

Thanks for the reply, BTW , to both of you.

 

[goninanbl00d]

It is not practical to offer all DPSS IR wavelengths, and that is from far a complete list.

For example, 1319nm (used to generate 659.5nm red), and and 946nm (used to generate 473nm blue) are not listed.

CNI, however, does list lasers at both 914nm, 946nm, 1319nm and 1342nm.

These lasers can be found here:

914 nm infrared laser.
Infrared laser, 946 nm infrared laser module, DPSS infrared lasers.
Infrared laser, 1319 nm infrared laser module,infrared lasers.

To determine the nm out, you need to know the gain medium that is being used in the laser. The pump wavelength is selected to match the absorption spectra of the gain medium, and is not directly involved with the output wavelength.

808nm is used to pump Nd:YAG and Nd:YVO4, as both substances have absorption bands at 808nm. If a different gain medium is used that has different absorption bands, the pump wavelength will change accordingly.

Other than that, it's dependant on the gain medium, and the cavity optics (including the non-linear optics).

The gain medium may have more than one lasing line (this is the case with Nd:YAG and Nd:YVO4). Depending on the cavity optics, any one of these lines may be selected and doubled.

The final output wavelength also depends on the non-linear optic used. For example, KTP will not double below 500nm, meaning that LBO or BBO must be used.

Hope this helps,

 

[GreenBeam]

It is not practical to offer all DPSS IR wavelengths, and that is from far a complete list.

For example, 1319nm (used to generate 659.5nm red), and and 946nm (used to generate 473nm blue) are not listed.

CNI, however, does list lasers at both 914nm, 946nm, 1319nm and 1342nm.

These lasers can be found here:

914 nm infrared laser.
Infrared laser, 946 nm infrared laser module, DPSS infrared lasers.
Infrared laser, 1319 nm infrared laser module,infrared lasers.

To determine the nm out, you need to know the gain medium that is being used in the laser. The pump wavelength is selected to match the absorption spectra of the gain medium, and is not directly involved with the output wavelength.

808nm is used to pump Nd:YAG and Nd:YVO4, as both substances have absorption bands at 808nm. If a different gain medium is used that has different absorption bands, the pump wavelength will change accordingly.

Other than that, it's dependant on the gain medium, and the cavity optics (including the non-linear optics).

The gain medium may have more than one lasing line (this is the case with Nd:YAG and Nd:YVO4). Depending on the cavity optics, any one of these lines may be selected and doubled.

The final output wavelength also depends on the non-linear optic used. For example, KTP will not double below 500nm, meaning that LBO or BBO must be used.

Hope this helps,

WOW, thanks, it's really involved with the crystals... not just the IR.

The "multi-Lasing line" in the crystal ... is this how the crystal goes out of alignment, not striking the exact Lasing line, and shows either IR thru, or another color blends in, instead of the desired one?

How to align the crystal, if needed? (expensive equipment?)

 

[goninanbl00d]

To select a lasing line from a multi-line capable gain medium, different cavity mirrors and optical coatings that reflect at the selected wavelength, and pass other wavelengths in that crystal are used. These ensure that only the selected wavelength can lase.

With the IR leakage, that's a different issue altogether. In this case, the crystal is no longer in line (or phase-matched, depending on the gain medium) with the pump source, and lasing can no longer occur. Instead, this pump light travels through the medium and out the aperture.

What you're referring to (one line taking over another) is something different once again. This happens in multiline crystals, where one lasing line is significantly more prominent than the others.

For example, Nd:YAG can be doubled to produce 532nm, 659.5nm and 473nm. The 1064nm line is the strongest, while the 473nm line is the weakest. Both the 1064 and 1319nm lines will compete for energy with the 946nm line (which is needed).

Crystal alignment depends on a lot of things, including the crystals used. Relatively insensitive crystals such as the common bonded YVO4/KTP sets can be aligned at home, while more complex crystal sets require instruments and/or a special atmospheric chamber.

 

[GreenBeam]

To select a lasing line from a multi-line capable gain medium, different cavity mirrors and optical coatings that reflect at the selected wavelength, and pass other wavelengths in that crystal are used. These ensure that only the selected wavelength can lase.

would this be the case to create 532nm & 457nm ?
... can a DPSS module for 532nm be taken apart, replace the 808nm diode
for 914nm, and Nd:YAG crystal for LBO or BBO, to use the 914nm and LBO or BBO, to make the 457nm ?
... or is this LBO or BBO crystal more complex and needs the special equipment to align?

I'm trying to understand what's actually inside these modules.
- For example; 532nm, and the differences for 457nm.
Do some need extra mirrors, within the modual,
to direct it at a special area on the crystal?
Are there any "schematics" or "pictorials" of the assemblies?

Any documentation available on the crystal properties and what/when to use them along with the IR nm required?
Along with the ones that can be aligned "at home".

With the IR leakage, that's a different issue altogether. In this case, the crystal is no longer in line (or phase-matched, depending on the gain medium) with the pump source, and lasing can no longer occur. Instead, this pump light travels through the medium and out the aperture.

could this happen during shipping, or by bumping the module or pen, knocking the alignment off?

What you're referring to (one line taking over another) is something different once again. This happens in multiline crystals, where one lasing line is significantly more prominent than the others.

For example, Nd:YAG can be doubled to produce 532nm, 659.5nm and 473nm. The 1064nm line is the strongest, while the 473nm line is the weakest. Both the 1064 and 1319nm lines will compete for energy with the 946nm line (which is needed).

Crystal alignment depends on a lot of things, including the crystals used. Relatively insensitive crystals such as the common bonded YVO4/KTP sets can be aligned at home, while more complex crystal sets require instruments and/or a special atmospheric chamber.

thanks for this info, it's really informative... I like lasers more now than before.

 

[mfo]

Thanks guys, but I do have one more question. It pertains to divergence and beam specs. We all know DPSS = the best beams, so therefor the green will be the nicest. So, will an olike green module + 445 + SMoC red module all work together? I choose the SMoC because no wings, less splash than the LOC or LCC. Thanks.

Also, who's doing RGB kits now days?

 

[goninanbl00d]

@mfo, As far as I know, nobody is making kits these days. I haven't heard anything about the White Fusion since I joined, and I have no idea what's happened to it.

As for combining those three beams, it will work, even though the beam diameters are different.

There will be visible 'halos' around the beam, however, in most cases the combined beam will drown these out completely, and they will not be noticable.

However, if you're going for beams, you might want to take note of the 445's divergence issue, with the fast axis diverging much faster than the slow axis. Although it won't be noticable close up, once you start going for longer beams >10m, it does become visibly noticable.

@GreenBeam, I should have pointed you here earlier, I've compiled quite a fair bit of this stuff into a guide. That way you can get the whole picture about everything I'm talking about, instead of me confusing you with bits of information.

Link: http://laserpointerforums.com/f44/dpss-primer-how-lasers-work-59797.html

 

[mfo]

@mfo, As far as I know, nobody is making kits these days. I haven't heard anything about the White Fusion since I joined, and I have no idea what's happened to it.

As for combining those three beams, it will work, even though the beam diameters are different.

There will be visible 'halos' around the beam, however, in most cases the combined beam will drown these out completely, and they will not be noticable.

However, if you're going for beams, you might want to take note of the 445's divergence issue, with the fast axis diverging much faster than the slow axis. Although it won't be noticable close up, once you start going for longer beams >10m, it does become visibly noticable.

@GreenBeam, I should have pointed you here earlier, I've compiled quite a fair bit of this stuff into a guide. That way you can get the whole picture about everything I'm talking about, instead of me confusing you with bits of information.

Link: http://laserpointerforums.com/f44/dpss-primer-how-lasers-work-59797.html

The 445 diodes still have bad divergence even at lower currents? I could have sworn pullbangdead said something about when using low currents, only one emitter is used so therefor the specs of the beam is MUCH better than what we typically drive them at. I will have to investigate further.