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Registered Member #311
Joined: Sun Mar 12 2006, 08:28PM
Location:
Posts: 253
Random info on this subject : many years ago I was given a very old Nd:YAG (or similar) laser made by a UK company - 1970's vintage I think. This used two linear halogen filament lamps in a dual-parabolic cavity with water cooling. There was a motorised Q-switch - this was simply a motor with a cylindrical block on the shaft with a cross hole (may have been 2 holes at 90 deg). Motor looked fairly fancy so possibly very fast, or it could just have been synchronisable, anyway it had a big controller and looked very expensive!. Lamps were 110v, control was via a dual-gang 2x8A variac. I suspect the lamps were heavily over-run as it came with a lot of spares! Never fired it up though... ended up swapping it for a TC cap. I believe some YAG medical lasers use (Krypton or Xenon arc?) discharge lamps for CW operation - saw one at an auction once but too heavy to consider!
Registered Member #2919
Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652
Halogen lamp-pumped YAGs are very inefficient; the emission spectrum of a halogen lamp does not match the absorption spectrum of Nd:YAG very well. If a YAG has a motorized Q-switch, it has to spin very quickly, as Nd has a short fluorescence lifetime. Medical YAGs are pumped by krypton arc lamps. Even then, they are pretty inefficient (my 50W Quantronix 117 draws 20A of 208V 3-phase). The really nice modern YAGs are pumped by laser diodes.
Registered Member #2919
Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652
Per unit of what? Power? Laser? What relation are you looking for? Lamp-pumped YAGs can be had cheap on the surplus market. Diode-pumped YAGs are less cheap (read: several kilodollars). Surplus pump diodes are pretty cheap. There's an Ebay seller who is selling 6 brand-new water-cooled diodes which are probably 60W each for $199. The used 20W conduction-cooled ones generally go for $25 to $35.
Registered Member #2919
Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652
But if you want high-powered CW operation, and don't want to lug around a 600 lb chiller+power supply, DPSS is the only way to go. There's always CO2, but that can't be doubled to green.
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Homemade flash-lamp pumped lasers
