TEA laser exciting dye

[Zoof]

Found this on youtube:
http://www.youtube.com/watch?v=JduZT...eature=related

and wondered why TEA lasers are not represented here on PL...

[The_Doctor]

Nice demo, but I don't understand it all. While N2 can lase without mirrors, at least, just one to send all the beam one way, what's happening with their dye cells? I noticed a slight movement of a spot as one cell was moved out of the N2 beam, suggesting that it has mirrors forming a cavity, but I can't see any mirrors on the cells. Nor around them, and if there were some around them, they'd have to be coated for each wavelength used, so what's going on? Is dye like N2 and Cu vapour, in not needing a full cavity of two mirrors to lase? If so, I can imagine a broadband HR mirror behind the cell, on axis with the coloured spots, but I thought dyes didn't lase that easy.

[Zoof]

Nice demo, but I don't understand it all. While N2 can lase without mirrors, at least, just one to send all the beam one way, what's happening with their dye cells? I noticed a slight movement of a spot as one cell was moved out of the N2 beam, suggesting that it has mirrors forming a cavity, but I can't see any mirrors on the cells. Nor around them, and if there were some around them, they'd have to be coated for each wavelength used, so what's going on? Is dye like N2 and Cu vapour, in not needing a full cavity of two mirrors to lase? If so, I can imagine a broadband HR mirror behind the cell, on axis with the coloured spots, but I thought dyes didn't lase that easy.

I noticed that too, I figured that the dye is super radiant so the dye cell would also lase without mirrors. If there were external cavity mirrors the alignment would be critical and he would not get the dye to lase by simply moving the dye cell around..... also the beams shoot out at both ends. The beam is surprisingly round too.

[The_Doctor]

The beam is surprisingly round too.

Indeed it is. I should have noted that and the one coming out the back. All very strange. Looks like something about those cells isn't obvious from the image.

[mixedgas]

because even at 250 uJ a pulse, the average dye laser output power is .5 mW or so. You'd need a meter long high rep rate N2 to do anything. N2 has its place in generating small amounts of amazingly tunable dye laser light for spectrscopy and micromachining and rangefinding. Increadbly short high peak power pulses, but very low average power.
for example:
http://www.ltb-berlin.de/mnl100.html

you'd be better off with qswitched doubled yag doing your pumping, and 2-3 watts of pump might get you 250-400 mW of red. I have dye lasers and N2 lasers, anytime you want to come over, I might be troubled to set one up.

A spektronika CVL pumped dye might be a nice option as well.

dyes are messy. They dont last long. Most people today don't want to be, nor have the skills to be, laser jocks, they just want their experiment to run, so they tend to go with commercial lasers , rather then do what just might make sense.

Steve

[mixedgas]

that is because your looking at superradient lasing. No mirrors required, no feedback required, , = 2 beams.

BTDTGTS

Steve

[The_Doctor]

I've started looking up superradiance, and already found an anomaly:
http://www.bnl.gov/bnlweb/pubaf/pr/P...asp?prID=07-08
That says the first observation is very new, in an article dated 19th Jan 2007. The N2 and dye thing has surely been seen much earlier than this? It looks like the sort of thing someone might see when putting a dye cell in the beam just to see what happened, long before they started in with mirrors and cavities. So if it is superradiance, why is an article claiming it's only been observed so recently as 2007 and in a much more extreme laser system?