High preformance DPSS Laser- a New Video

[planters]

I have nearly completed a DPSS laser that I have been working on for some time. There are some neat features that may be of use to others and a brief discussion of things to think about when building solid state lasers, including some pitfalls. I hope you enjoy it and I welcome your feedback.

https://www.youtube.com/watch?v=Pp9hliLJjg4

[polishedball]

Can't wait to watch tonight. Thanks in advance for the vid. I know already it will be well worth the watch.

[krazer]

Very nice looking! It will be very interesting to see what happens when you get the second diode in and start increasing the power

[SoulFeast]

That was a wonderful video to watch! I loved how detailed you went in your explanations. DPSS is outside of my realm of deep understanding, so it was nice to have all the finer points explained.

[Galvonaut]

Thank you so much for posting your video Planters. It was thoroughly enjoyable and I learnt a lot from it.

That beam is pretty slick and something I can only dream of when building my RGB over the coming year.
For all intents and purposes (unless you are using the beam several miles away from the laser) that seems like negative divergence. Do you know if it is possible to increase the distance of the focal point of Chinese DPSS lasers to any reasonable extent using optics?

Thanks
Keith

[steve-o]

Gongrats Planters for completing the "Gig Green" Project. You deserve a PL Gold Award for that one. That looked a lot more difficult than I would have imagined. The yellow and orange will be an amazing plus to your accomplishments also. Awesome video and project build (as usual.) Thanx for sharing the info :-] *Five Thumbs-Up*

[planters]

Very nice looking! It will be very interesting to see what happens when you get the second diode in and start increasing the power

So far so good. Above 3.6W with a single pump there start to be some multimode components that actually decrease when the second pump stars to feed even a little power. I think this is due to the two ends of the crystal (10mm apart) representing distinct gain regions. The absorption depth is so shallow that nothing like a cylindrical gain path is occurring and so the only commonality of the two gain discs on each end is the TEM00 mode. I haven't run it above 5W yet. Slow but steady.

For all intents and purposes (unless you are using the beam several miles away from the laser) that seems like negative divergence

You can do the same thing with any laser. That's why divergence can be so misleading. Take a Laserwave (I have a couple laying around). The exit beam is 3mm and the measured spot is 25mm at 20M. The net 22mm over 20,000mm is a divergence of 1.1mrad. Now, telescope the beam to 12 mm in diameter. The spot at 20M will probably something above 6mm in diameter, but less than 12mm. This isn't a negative divergence, rather it is a demagnification of the far field spot that overwhelms the beam expansion due to fundamental aberrations in the beam. The quality of the "Z fold" is that this is happening with a 3mm exit beam. And to be fair the spot doubles to 2mm in diameter at several watts output, but then it bores a hole in the wall.

[Displaser]

Another great video. More wavelengths has my attention. Thanks for putting these videos out there.

[Galvonaut]

You can do the same thing with any laser. That's why divergence can be so misleading. Take a Laserwave (I have a couple laying around). The exit beam is 3mm and the measured spot is 25mm at 20M. The net 22mm over 20,000mm is a divergence of 1.1mrad. Now, telescope the beam to 12 mm in diameter. The spot at 20M will probably something above 6mm in diameter, but less than 12mm. This isn't a negative divergence, rather it is a demagnification of the far field spot that overwhelms the beam expansion due to fundamental aberrations in the beam. The quality of the "Z fold" is that this is happening with a 3mm exit beam. And to be fair the spot doubles to 2mm in diameter at several watts output, but then it bores a hole in the wall.

That's interesting Planters. Thank you.
When you demagnify, as well as reducing spot size, do you reduce intensity or change other beam characteristics?
What length of optical path do you think you would need to take, say a 5mm beam down to 2mm?
I ask as I plan to build a single mode (if I can afford it) RGB projector for graphics use and until now, understood that good beam specs were dependent on how much you spent on the laser itself - not the optical set-up.

Keith

[SoulFeast]

What are your plans for obtaining orange without using a 444nm pump source? The only DPSS oranges I know of (604nm and 607nm) uses a 444nm pumped Pr:YLF / Pr:PAYAC (respectively).