hi, i was looking at the spectrometer plot on the yellow laser on the ledmuseum website http://ledmuseum.candlepower.us/yelldpss.htm and shouldnt the graph have two spives, one at 532nm and the other at 671nm? because an 808nm diode pumps a crystal (i have no idea which crysal) which lases at 1064nm as well as 1342nm and then this goes into another crystal (ktp i think) and that frequency doubles it to 532nm and 671nm which, mixed together make a yellow\orange color or does the ktp "combine" the two wavelengths to make 593.5nm?
yellow laser spectrometer plot?
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The_LED_Museum
*Retired*
There are two minor emissions at 532nm & 671nm, but they are far too weak to show up on the spectrometer.
I have observed them by viewing the laser off-axis during warmup, but I was not able to capture them via spectroscopy.
I have observed them by viewing the laser off-axis during warmup, but I was not able to capture them via spectroscopy.
the laser is probably filtered with HR ( highly reflective) coatings in the optics or between crystals in the cavity. same idea of how greens work you can actually make a beam much stronger by having it reflect around a few times inside of a crystal and only let one wavelength out.
The_LED_Museum
*Retired*
From a laser engineer who emailed me, comes the following text:
The technology behind the yellow laser is a bit more involved than in the green laser, involving a process called sum frequency generation. It uses the same components that the green laser has, but the coatings are much different.
There are two particular "tricks" in making a sum frequency laser. The first is to get a single laser crystal (the Nd:YAG or Nd:YVO4) to lase simultaneously at two different wavelengths, both 1064 nm and 1342 nm. While we do this with gas lasers (Argon and Krypton) frequently, this is pretty rare with solid state. The relative powers of the two have to be in a reasonable range for the sum frequency process to work. The two waves are introduced in to the KTP crystal, which generates the 593.5nm output.
The technology behind the yellow laser is a bit more involved than in the green laser, involving a process called sum frequency generation. It uses the same components that the green laser has, but the coatings are much different.
There are two particular "tricks" in making a sum frequency laser. The first is to get a single laser crystal (the Nd:YAG or Nd:YVO4) to lase simultaneously at two different wavelengths, both 1064 nm and 1342 nm. While we do this with gas lasers (Argon and Krypton) frequently, this is pretty rare with solid state. The relative powers of the two have to be in a reasonable range for the sum frequency process to work. The two waves are introduced in to the KTP crystal, which generates the 593.5nm output.
The_LED_Museum
*Retired*
Here is a spectrographic analysis, deliberately overexposed to show the weaker 532nm, 671nm, and (to an extent anyway) 808nm spectral lines.
(Edit) The graphic shows "1,064nm"; it should read "808nm".
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The_LED_Museum
*Retired*
Ok, I was successful this time. 
Note the prominent spikes at 532nm and 671nm. :thumbsup:
Note the prominent spikes at 532nm and 671nm. :thumbsup:
SenKat
Enlightened
SWEEET ! THat answers a few questions I had rolling around in my head, too ! Thanks for that.:rock:
