532 DPSS vs 520 DI

[norty303]

I seem to recall I read a lot of speculation about the lower wavelength being less visible than 532, and yellows being worse, but I'm not sure we ever went back and covered general brightness, watt for watt.

Well, I don't know about your experiences, but taking 2 modules of pretty much the same CW output power (CNI MGL-H or Laserwave heads), in a show environment, I can clearly say that the DI 520nm laser kicks the DPSS butt quite conclusively.

Quite simply, the poorer modulation of DPSS really gets shown up next to the DI. Its like free watts.

Anything new for me will now use full DI (and actually have been for the last 18 months or so)

[buffo]

That's interesting... I've had the opposite result. I find that 532 seems to stand out far better than 520, even at identical power levels.

I do agree that the modulation of the 520 is far superior, which is why I prefer 520 for graphics. But for beam work, I think 532 trumps the 520. It just looks brighter.

Admittedly though, I have only done side-by-side comparisons up to around a watt of each. Perhaps at multi-watt levels the modulation losses are more apparent.

Adam

[norty303]

My tests have been at the sub-watt level too.
TBH I don't even see the colour difference. Perhaps this actually comes down to the quality of the DPSS modulation, and yours may be better.

Being able to do linear colour fades to blackout is something to behold though. And really obvious with the different technologies side by side. Also, having BAMs that don't change colour with brightness is a real bonus

I suspect setting up good custom colour maps in Beyond would help with that, but as I have different projectors connected to different FB3s pretty much every gig, it would be hard to achieve. I'm not sure if you can save colour configs for Beyond/FB3 (I know the QM has the colour trainer separately), that might be my fix...

[sbk]

A very interesting thing to do now is to test your green diodes on a spectrometer! If it's lasing at 525nm rather than at 515nm (the min-max wavelengths according to datasheet), brightness and color will be much closer to a DPSS.

Also the beam diameter and divergence can play a significant role here...

[drm916]

i have some pictures that show the difference clearly. I am out of town for a death in the family but I can FB you the photo.

johnathon

[Draco]

When you guys mention modulation, i am assuming the control from the projectors controller? what does the difference look like?

[absolom7691]

It's possible that you have higher wavelength diodes. The very first 520 I got is probably closer to 515. The later ones are probably nearer to 525. With my new and old diodes, side by side, I can see a difference in the color.

[absolom7691]

When you guys mention modulation, i am assuming the control from the projectors controller? what does the difference look like?

Yes, from the controller or DAC. DPSS lasers can be very sensitive to internal temperature fluctuations. As such, when a DPSS is being modulated, the output can vary. Even "name brand" DPSS lasers can do this. It makes it very difficult for color balance and also brightness uniformity in general. Diodes don't suffer from this problem, or if they do, it is on a scale that can't be detected by the human eye. My 200mW green DPSS would fluctuate wildly until warm. The output would vary by 10's of mW.

[norty303]

I think it's more down to the modulation characteristics in that DI rise time to full power is better and more consistent

[Draco]

I was going to get a low power 520nm this month but my vehicle decided it wanted a new starter, there went that idea.