White laser in the snow

John Klayer · Post by **John Klayer** » Mon Mar 04, 2013 4:13 pm

I just bought a RGB white laser. I shined it into a light snow storm Saturday night in north Georgia. The beam was real beautiful, like a line of blinking psychadelic Christmas lights. I wonder why. If the red, green and blue are all CW and aligned together, shouldn't the snow flake reflections be white?

Dinesh · Post by **Dinesh** » Mon Mar 04, 2013 4:37 pm

John Klayer wrote:If the red, green and blue are all CW and aligned together, shouldn't the snow flake reflections be white?

No, because it's scattering and refracting through layers of clumped and irregular snow and possibly some layers of melted water. Due to the change in refractive index of water for the various wavelengths, you get a separation of the spectra, which is amplified by multiple reflections within the snow. What you saw was a sort of "upside down" rainbow. However, because the laser contains only three components, you don't see the continuous spectrum of a rainbow, but only specific components, thus the "christmas light" look. You can see this better if you pass the white laser through a low-frequency transmission grating

holomaker · Post by **holomaker** » Mon Mar 04, 2013 5:32 pm

John what type/make laser? Is it SLM?

John Klayer · Post by **John Klayer** » Mon Mar 04, 2013 9:29 pm

It is from Laserlands on eBay. For $126, I doubt that it is SLM. I just wanted a white laser to play with. I'll make some kind of TTL controller to change the colors. I ordered it on a Thursday evening and had it the next Monday.

Jeffrey Weil · Post by **Jeffrey Weil** » Mon Mar 04, 2013 10:33 pm

http://www.ebay.com/itm/200mw-RGB-White ... 19d74ccba8

John Klayer · Post by **John Klayer** » Mon Mar 04, 2013 11:44 pm

Yeah, mine is just like that except for an extra $27 I got double the power, 400 mW. Probably the difference is the adjustment of the three pots on the circuit board. I really don't have a holographic use for it. Just thought it would be fun to play with. If someone wanted to do light shows, this would be a cheap way to start. There is a discussion about it in Photonlexicon under Lasers All Kinds - Cheap Chinese RGB Worth It?

Ed Wesly · Post by **Ed Wesly** » Tue Mar 05, 2013 11:39 am

Put the beam through stacks of the gratings I had contributed to the "box" for Christmas lights at any time of the year! There are some marked Xmas gratings or Ultra Low (Spatial) Frequency gratings, shot with just a couple of degrees between the two beams, and there might be as many as 7 or 9 orders coming out of it! A stack of them will give plenty of satellites!

If you spread that laser's beam with a lens or spatial filter, and send it through the included zone plate, you will see the R, G, and B focus at different depths.

Have fun! Wish I could buy one of those little toys!

Ed Wesly · Post by **Ed Wesly** » Tue Mar 19, 2013 3:44 pm

So I dropped $100 of my hard-earned pay on that laser, and it arrived today, however there is no power supply supplied! No instructions, the laser, and just a baggie with three wires, that look like they plug into the circuit board, but nothing for their other ends to plug into!

How are you running these things?

MilanKarakas · Post by **MilanKarakas** » Wed Mar 20, 2013 12:22 am

Ed Wesly wrote:So I dropped $100 of my hard-earned pay on that laser, and it arrived today, however there is no power supply supplied! No instructions, the laser, and just a baggie with three wires, that look like they plug into the circuit board, but nothing for their other ends to plug into!

How are you running these things?

It seems that it is 'call' for another $100 to power up.

Do you have at least specification of the output power for each laser inside? It is possible to guess what laser diode is within some error, but most of the laser diodes and DPPS lasers are pretty the same. Out there are lot of datasheets about various laser diodes, but I need to know exact specs - at least of max power or so.

If you want, please send me PM, and perhaps include some photo of your device. I will try to help you power it.

Best--
milan

John Klayer · Post by **John Klayer** » Wed Mar 20, 2013 4:54 am

The blue, red and green sockets are for the TTL controls. The white socket next to them is for 12 VDC, look close and see it is marked in small letters +12V and GND.