Right, I understand that, but what I was actually asking is, how come it works well with a 1064 Nd:YAG DPSS source but not a diode? I guess it's because the YAG is much more stable than the diode?
There I go answering my own question again.
Senior Member
Right, I understand that, but what I was actually asking is, how come it works well with a 1064 Nd:YAG DPSS source but not a diode? I guess it's because the YAG is much more stable than the diode?
There I go answering my own question again.
Senior Member
If I read what steve said correctly, then it works with YAG+KTP because when the 808nm pump hits the YAG then that lases at 1024nm ( plus a bunch of other weaker lines which get blocked by the mirrors anyway ) and that creates a single frequency laser, which can be doubled more easily than if the 808nm pump went straight to the doubling crystal.
-Adam
Senior Member
OOOOOH!!!! No, I get it. You need to be intracavity because otherwise you can't get enough orbitals to line up. The recirculating power inside the cavity gets you that kind of crazy energy density, and of course inside the resonator it's all coherent. YES. I understand now! Thanks Steve!
Creaky Old Award Winning Bastard Technologist
Originally Posted by heroic
The crystal is oriented at cutting using x-ray diffraction. It is temperature sensitive, polarization sensitive and to a certain extent, bandwidth sensitive.
It wants to see a huge amount of energy, and that energy had better hit the lattice and orbitals in exactly the right pattern in time and space. Since there are two different types of crystals, they want to see radical differences in how they are used, ie a type II shg may not be happy where a type I works just fine. Oh, and they bite back, if your close to their desired working regime, they may tease you by pulsing, or distoting the beam or blowing up. And they need 6 axis adjustment on the crystals, at least untill the factory nails down how to orient them
It really takes about 5 years to understand it, and I have been working on gas for years, so I'm behind on soild state. See doubled solid state are pretty much throw aways if something goes wrong. Yeah you can change a lamp, or a crystal or a rod, but you really are stuck with how the factory set them up.
Gas lasers are much, much easier to design, long term and a lot more flexible in cavity design.
Steve
Creaky Old Award Winning Bastard Technologist
You can be extracavity if the laser is dumping huge fast pulses, or if you a one of newer supermaterials that has a lower threshold, but they work mainly in the IR and so are no concern to us here, YET.
Steve
WOW! Thanks for all the Great info Steve! I found it clear to understand and informative. So, due to the fact that it's a diode array, minute temperature fluctuations between say, diode 1 and 16 may have a wavelength difference as much as 1nm or so. Sounds like I may have to put the insulation back on the hoses inside my chiller and externally to achieve even more stability.
Is it that Nd: YAG is more forgiving to a few nm of instability or does it have to do with it being a better gain medium than an SHG crystal? Or a little bit of both?
Yeah, forget that quad mirror bow-tie cavity stuff.I'm gonna have a hard enough time with a Z fold cavity if I can't find some laserscope guts for a deal.
Also, that YAG I pointed out to you the other day. Since it has brewster angles (at least I think that's what they are) incorporated into it, Will I run into any possible polarization issues with the KTP or are they purely benificial?
Senior Member
Not to forget that thermal lensing will have a level fun in the experiments...Good article....Steve's condensed quantum primer of DPSS lasers...
You are the only one that can make your dreams come true....and the only one that can stop them...A.M. Dietrich
Creaky Old Award Winning Bastard Technologist
OK< DEPENDS OH HOW THE KTP IS CUT< YOU MAY HAVE TO ROTATE THE ROD ALONG ITS AXIS. NORTHRUP GRUMMON CAN TELL YOU IF YOU ASK. NG SYNOPTICS DIV MADE LASERSCOPE KTP>WOW! Thanks for all the Great info Steve! I found it clear to understand and informative. So, due to the fact that it's a diode array, minute temperature fluctuations between say, diode 1 and 16 may have a wavelength difference as much as 1nm or so. Sounds like I may have to put the insulation back on the hoses inside my chiller and externally to achieve even more stability.
Is it that Nd: YAG is more forgiving to a few nm of instability or does it have to do with it being a better gain medium than an SHG crystal? Or a little bit of both?
YAG ADSORBS OVER A BROAD RANGE AND RERADIATES ON ONE NARROW LINE. YOU ADJUST THE DIODE TEMPERATURE TO MATCH THE ADSORBTION RANGE, WHICH IS ABOUT 8 NANOMETERS WIDE, I DOUBT ITS THAT MUCH OF A ISSUE< YOU"LL JUST SEE SLOW FLUCTUATIONS IN POWER IF YOU HAVE IT WRONG>
Yeah, forget that quad mirror bow-tie cavity stuff.
HUM, DEPENDS ON HOW MUCH THERMAL LENSING YOU GET< MAY HAVE TO ADJUST THE LASERSCOPE MIRROR SPACING!
Also, that YAG I pointed out to you the other day. Since it has brewster angles (at least I think that's what they are) incorporated into it, Will I run into any possible polarization issues with the KTP or are they purely benificial?
IF THS IS THE BREWSTER \\ then ^ UP THE PAGE is VERTICAL POLARIZATION.
STEVE
Yes, Steve and I discussed that. Since the YAG is square. I was planning on putting TEC's on top and underneath hopefully this will counteract some of the thermal lensing since I plan on pumping the rod from only one side. We'll see.
P.S. Where can I find said article? I looked on PL and Sam's Laser FAQ.
OK< DEPENDS OH HOW THE KTP IS CUT< YOU MAY HAVE TO ROTATE THE ROD ALONG ITS AXIS. NORTHRUP GRUMMON CAN TELL YOU IF YOU ASK. NG SYNOPTICS DIV MADE LASERSCOPE KTP>
IF THS IS THE BREWSTER \\ then ^ UP THE PAGE is VERTICAL POLARIZATION.
STEVE
Got it! I'm sure I can get a stability between 808nm +/-4nm.
As for polarization, that's what I thought. Thanks for clarifying.
Last edited by 300EVIL; 03-10-2009 at 16:39.
Creaky Old Award Winning Bastard Technologist
probably no amount of te or h20 will reduce the lensing to zero.
Steve
Posting Permissions
Reply With Quote
300EVIL