Old 06-01-2015, 12:18 AM #17
diachi's Avatar
Class 4 Laser
 
Join Date: Feb 2008
Location: Yellowknife, NT, Canada
Posts: 7,114
Rep Power: 7161
diachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond repute
Send a message via Skype™ to diachi
diachi diachi is online now
Class 4 Laser
diachi's Avatar
 
Join Date: Feb 2008
Location: Yellowknife, NT, Canada
Posts: 7,114
Rep Power: 7161
diachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond reputediachi has a reputation beyond repute
Send a message via Skype™ to diachi
Default Re: Little help to understand SHG

Quote:
Originally Posted by Alaskan View Post
I liked this article:

http://photos.imageevent.com/qdf_fil...roject/nlo.pdf

I'm searching for information regarding what happens if you use 810nm, or to throw a number out there, 815nm instead of 808nm, how far from 808nm can the pump be off wavelength/frequency into the vanadate and then KTP before the 532nm output either doesn't work, or begins to drop off by 10 percent? Which crystal suffers the worse conversion efficiency when off freq, the YVO4 vanadate or the KTP, or do they both have similar off-wavelength inefficiencies?

Maybe I'm looking at this wrong, for example, if you shoot 1070nm into a LBO or KTP crystal you just end up with half the wavelength out or 535nm? Are all "532nm" DPSS laser pointers really 532nm?
From the Laser FAQ:

Quote:
The absorption curve of Nd:YVO4 (vanadate) is quite broad compared to Nd:YAG (YAG). The following is from a graph in "Solid State Laser Engineering" by Koechner. (This actually deals with output power, not absorption, but since that is the desired effect, the numbers should be similar):
Nd:YVO4: Between 806 nm and beyond 813 nm, the output power is approximately constant. The corresponds to a temperature range of 20 C for the pump diode. The output drops to 50 percent at about 801 nm. (The graph doesn't go higher than 813 nm.)
Nd:YAG: The peak is between 809 and 810 nm with the output power down by 40 percent at 807 and 810 nm.

For pumping with diodes, the wider wavelength range of vanadate is very significant because temperature tuning is a lot less critical and for low power DPSS lasers such as green laser pointers, thermal management isn't essential (though some variation may still be evident).
I was just going to say "Vanadate has a wider absorption band than YAG" but thought some numbers would be nice, so dug that out!

Edit: Just realized you were asking about Vanadate vs KTP - the thing there is that the Vanadate will always output at 1064nm (assuming you're using optics for 1064nm) so that will not be an issue for the KTP. The issue comes from the diode's wavelength shifting and then causing the output from your Vanadate to drop due to reduced adsorption. Temperature is the biggest concern for KTP, even if the temperature is a degree or two out you can see a large drop in efficiency. You can also run into thermal lensing in your Vanadate and possibly to some extent in the KTP which causes overall efficiency issues in many designs. That can also cause a reduction in beam quality.

Yes, all of the 532nm lasers are 532nm within a very small margin.


__________________


445nm | Sanwu Laser Pocket Series | 400mW Metered
445nm | NDB7242E Pen Build | 60mW Metered | >>Build Thread<<
488nm | Spectra Physics 163 Argon | ~30mW Metered
515nm | PL515 Pen Build | 50mW Metered | >>Build Thread<<
520nm | Laserlands 520 | 5mW | For Review Awaiting arrival
532nm | Gearbest 303 Pointer | 50mW Metered
532nm | Gearbest JD.850 Pointer | 30mW Metered (I think, need to re-test).
633nm | HeNe | 6mW
650nm | Sanwu Laser Pocket Series | 200mW Metered
808nm | Melles Griot 532nm Lab Unit | No Crystals >10W | X2

Last edited by diachi; 06-01-2015 at 12:26 AM.
diachi is online now   Reply With Quote








Old 06-01-2015, 01:35 AM #18
Alaskan's Avatar
Class 4 Laser
 
Join Date: Jan 2014
Location: Southwest Asia
Posts: 5,910
Rep Power: 6722
Alaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond repute
Alaskan Alaskan is offline
Class 4 Laser
Alaskan's Avatar
 
Join Date: Jan 2014
Location: Southwest Asia
Posts: 5,910
Rep Power: 6722
Alaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond reputeAlaskan has a reputation beyond repute
Default Re: Little help to understand SHG

Thank you, I've been reading a few parts of Sam's Laser FAQ and must have overlooked that, did a google search and my search terms must have been bad not to pick up on finding the FAQ... excuses, excuses.. Anyway, that mystery is solved, I've been wondering on the question for awhile but keep forgetting to ask anyone, so today I tailed the question on to this thread. I have some Vanadate, a nice piece 10mm X 10mm X 1mm someone gave me as a gift and a KTP crystal wrapped in gold leaf I bought from someone but before I start doing anything with it, needed to know how temperature affected the materials.
__________________

The forum costs more to run than donations received, if you wish to help click this link: http://laserpointerforums.com/donations.htm

Laser Safety: http://www.laserpointersafety.com/index.html

Sam's Laser FAQ: Sam's Laser FAQ: Welcome Page

RHD's Relative Perceived Brightness Calculator. Compare brightness @nm: http://lsrtools.1apps.com/relativebrightness

To shorten my signature I have moved most of my laser related web links to this forum page, the second post in that thread shows most of my builds... Alaskan's Laser Links: http://laserpointerforums.com/f44/al...ml#post1449395


Sincerely investigate any of these three short quotes as new concepts and you've taken your first step into a larger world:

"I regard consciousness as fundamental. I regard matter as derivative from consciousness..." - Max Planck. "Everything we call real is made of things that cannot be regarded as real" - Neils Bohr. "What we call physical things and events do not exist independently of subjective experience..." - Deepak Chopra.

Each of these three rabbit holes go deep, ending up in the same place.

Useless troll fighting.

Last edited by Alaskan; 06-22-2015 at 05:55 AM.
Alaskan is offline   Reply With Quote
Reply

Tags
dpss, ktp, shg





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Top 50 Laser Pointer Companies - Green Lasers Top 50 Laser Pointer Companies - Blue Lasers Top 50 Laser Pointer Companies - Red Lasers
Top 50 Laser Pointer Companies - Yellow Lasers Top 50 Laser Pointer Companies - Purple Lasers Top 50 Laser Pointer Companies - Orange Lasers
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes




Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 02:09 AM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC