Right now I’m shopping for a laser. Will it be a CVI Melles-Griot, or a Klastech, or Coherent, or Newport spectra physics, or what? The truth is I know very little about lasers, but I’m learning by necessity, which is one thing that’s great about research.
I’m interested in a DPSS 532 nm laser, where a 808 nm diode laser pumps an Nd:YAG (standing for Neodynium doped Yttrium Aluminun Garnet) crystal, where electronic transitions give rise to 1064 nm light most intensely. The 1064 light is selected out then sent through a frequency doubling crystal. Coatings and filters get rid of the remaining 808 and 1064 light.
Another thing I was needing to know was “what does the M^2 value mean?” regarding beam quality. I found out that, roughly, it is how similar a beam profile is to a Gaussian. It’s the ratio of the beam parameter product (BPP) of the beam to the minimum possible beam parameter product, that of a Gaussian beam, which wavelength/pi. Thus an ideal TEM00 single-mode 532 would have M^2 = 1. Thus since I’m interested in imaging with this laser by expanding the beam and want to take a nice slice of gaussian frosting to send to the objective, the Klastech with M^2 = 1.05 seems fit for the job. Cheers to Jim Doty for that and other good suggestions.
All for now… next posts hopefully will include raman spectroscopy of graphene, compressive sensing phase transitions, matlab, more laser stuff, something on high powered led options…
Lastly just found this blog ProfHacker while looking for info on having access to zotero bibs through WordPress blogs…he’s got info on that. Also one of his latest posts was on establishing a web presence, which happens to be one of my new year’s resolutions.
From "Encyclopedai of Laser Physics and Technology"
Sam's LaserFAQ