Recent content by brianpe

Nope. What you're talking about is second harmonic generation. Two photons of the same wavelength come in, and through some fancy quantum mechanics out pops one photon that's half the wavelength. There are so many variables getting any kind of efficiency out of this that you are much better...

I have a Coherent FAP housed in the full module with monitoring and TEC. The FAP is in pretty bad shape (emits 3W @ 30A). I have another FAP I want to swap in and reuse the TEC. I've removed most of the module but the FAP is bonded to the heat spreader with a thin sheet of indium foil and I...

Selecting parts is really hard -- there are so many. But unless you have specific needs (high power, fast switching, low noise) there are some standard parts you can start with. For op-amps, Dave on the EEVBlog has a good video on what he calls "jelly bean op-amps", which are generic, common...

I designed a control board that can do 53 amps 4v into two channels each for a dual end-pumped z-fold cavity. It's switch mode based on the MAX20096. It uses some pretty beefy MOSFETS and inductors and has a switching speed of 1Mhz so it's pretty clean. Can run on a 2s LiPo pack but it's...

I did try inserting a 1/2 wave plate and rotating that -- there was a small (5%) improvement depending on orientation. I haven't tried rotating the whole fiber. These FAPs have random polarization so they will lose some efficiency here for sure. The Verdi's use them into vanadate too so I am...

If you have a power meter you can test how well your current goggles work: defocus the laser and shine a somewhat broad beam through a pair of goggles and measure what comes through on your power meter. If that transmitted power is <= class 1, your current goggles are fine. Just be sure to wear...

Ok, so for the last couple of years I've been working on building a portable DPSS laser. It's a Z-fold cavity design powered by two 40W FAP modules. All electronics are battery operated by an integrated LiPo pack. At full tilt there is enough battery to run it for about 30 minutes. It's portable...

(Sorry, totally misread your question). No specific plans other than to learn how to do it and see what kind of power level I can achieve. I will frequency double it to green, and I want to try passive Q-switching once I understand enough to be reasonably confident I'm not going to ruin...

Z-fold is lasing! Only took me about seven hours to align it and still only using one pump. But it's miller time.

Thanks for this, it's great data and will come in handy as I dial in the z-fold. I figured out my alignment confusion. Well, I got some help from folks along the way. The alignment beam is going to deflect from the crystal for all sorts of reasons (crystal not totally parallel, refraction...

:) Ha. Been there, done that. I have plenty of things that pew pew. This one...this is more of a journey. And my wife hoping someday I will talk about something else. whysoserious - FAPs are Coherent FAP 40w. They are used but in good condition and temperature tuned to emit @ 808. I don't...

I've spent some time on this and no luck. First, my idea of using the IR leakage from my 532nm pointer is not going to work. Yes, it's cheap and leaks IR. But is just "spill" from spontaneous emission and not in the beam. If I put a visible block filter in front of it I get next to nothing...

This video shows a neat technique: Wavelength Division Multiplexing. He's using knife edging, but also a TEC cooler on each end of a group of diodes to create a temperature gradient. Since wavelength is temperature dependent, you can then take the independent beams from the knife edge array...

Thanks Tony. Will spend a few nights this week trying this out. Your green laser sparked an idea -- I have a cheap DPSS 532nm laser that spits out a bunch of 1064 light too. I have not been using it for alignment because while the label says < 5mw, my LPM says it's putting out about 60: way...

#2 is a planar mirror that's HR 1064 HT 808. But the black cylinder to the left is a combination collimator and focusing assembly. It's currently set to about 300um but with a lens swap I can get it down to about 150um at the crystal face. Unfortunately the light coming into this is a fiber...