Simple laser brightness question

[TroyX87]

Hi,
I have a RGY laser light I bought and use to DJ parties and events. It has a 605nm Red 100mw module and a 532nm Green 50mw module. Recently the red one has died (no idea how, has had maximum 100 hours use) and I've ordered a replacement. But I thought it would be cool to replace it with a purple laser instead, the ones I've seen on ebay are 405nm, and either 50 or 100mw.

My question is, with a wavelength lower than the others, do I need more power to compensate and keep up the brightness, or is it the other way around? I could get the 50, but dont want it to be weak, but then the red was 100mw and seemed darker than the green anyway. I want the purple to be nice and bright like the green but not overpowering. Would 100mw be too much?

Thanks guys

 

[InfinitusEquitas]

Hi,

Play around with this calculator one of the vets created/found... I think you'll find the results to be interesting: Beam: (402nm 1mw) vs. (420nm 1mw)

Basically what you will find is that it would take a very very powerful 405nm laser in order to match the 50mW green. Green is perceived a lot better by our eyes.

IMO if you have the money than try experimenting, but you're gonna have a hard time matching the brightness of the green beam.

In personal observation, I find that the beam from a 650nm 250mW laser is nowhere near as visible as even the beam of a 30mW 532nm.

 

[TroyX87]

Hmm, thanks for the response.

My next question would then be, whats the kind of comparison to a 632nm 100w red to a 405nm 100w purple? Would they be around similar brightnesses, so the red from before would look the same-ish but be purple instead?

 

[InfinitusEquitas]

Purple is much harder to see IMO. Personally I enjoy lasers mostly because of the beams, and that means sticking to 445nm and 532nm (Blue and Green).

I think you would be very well of investing a fog/smoke machine... having even a little particulate matter in the air will make the beams a lot more visible.

The perception of color varies a little from person to person though, and some find the 405nm to be very interesting.

If you had a red laser, and you're getting a red laser of the same power, you should see roughly the same results:thinking: With a little variance depending on exact wavelength. I think you might be disappointed by the purple 405 though.

 

[chipdouglas]

You wont be able to just put a violet in place of the red. there are special mirrors in there called dichros and they are color specific. so the ones that are in are for red and green. you can get ones to match. take a pic of your insides

michael.

 

[InfinitusEquitas]

Good point. I was only thinking about it in terms of 1:1 with beam brightness, but with other optics involved...

 

[TroyX87]

Hmm, very good point about the optics, that could really screw me up. Luckily when I had it apart once I took some shots, so here they are. If its gonna end up being too annoying, and the purple wont be that great then I probably wont bother. The thing on the top is just a motor, which connects a band to a little light splitter thing, shoots out about 50 red and green dots and moves to the music, its really cool.

Edit: Forgot to mention, I do have a smoke machine, and a strobe light, and very powerful speakers. My parties go off!

http://img830.imageshack.us/i/01062010574.jpg
http://img263.imageshack.us/i/01062010577.jpg

Here are the best shots I could find of it in action. 2nd shot was the only good one I had of what it actually shows. My friend was spinning around, the strobe went off twice in the 1 second exposure, acting as a flash, hence it caught the image twice

http://img825.imageshack.us/i/sdc12228.jpg
http://img690.imageshack.us/i/sdc11320p.jpg

Tried to show pictures but they wouldnt, hence the links