40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  TCS elog, Page 6 of 6  Not logged in ELOG logo
New entries since:Wed Dec 31 16:00:00 1969
ID Date Authorup Type Category Subject
  156   Tue Nov 29 09:13:49 2011 ranaMiscLIGO 3GSwitching from CO2 to shorter wavelength solid state laser

 Around a year ago, Phil and I discussed the possibility of using an OPO to possibly generate our own laser beam at ~2 microns for TCS. This was to avoid all of the usual hassle of the 10 micron CO2 laser.

As it turns out, the 1.5-3 micron range doesn't have enough absorption in fused silica: the absorption depth would be basically the whole thickness of the optics and this is not so useful when trying to correct surface heating.

During my recent trip to JILA, Jan Hall mentioned to me that it should be possible to operate instead at ~5 microns, where laser technology may be solid state and where we can use Si:As detectors instead of the inefficient HgCdTe ones which we use now.

JWST, in partnerships with industry, have developed some Si:As detectors:  http://www.jwst.nasa.gov/infrared.html   

Some internet searching shows that there are now several laser technologies for the mid-IR or MWIR range. Some are <1 W, but some are in the ~10 W range.

Of course, its possible that we'll switch to Silicon substrates, in which case we need to re-evaluate the goals and/or existence of TCS.

ELOG V3.1.3-