Goals and restrictions:

• Use the fewest lenses as possible.
• The beam widths in both onward and reflection direction should be such that there is a 5-inch space somewhere where we can put in the faraday isolator which has an aperture size of 3 mm and intensity limit of 500 W/cm².
• The lens should not be closer than 1.5 inches from each other or to the EOM mount or cavity edge.
• Choose a lens from a list of focal lengths available in west bridge labs.
• Find the best overlap with the target beam of 18 um at the cavity waist with the most sensitivity with respect to lens positions.

Analysis & Results

• CavityLens.m is run to try all possible lens combinations for 2-lens or 3-lens solutions using ../20201222_BeamProfileNeatEOM/SeedBeam.mat as the seed beam.
• Then save solutions with more than 70% overlap in CavityModeMatchingSolutions.mat.
• findBestSolutions.m increases the overlap threshold to 0.9, calculates reflected beam profile for the sideband reflection from the cavity (blue curves in the figures), and discards solution which does not have a 5-inch long area where we can place a faraday isolator with aperture of 3 mm.
• Black lines show the region where Thorlabs IO-3-1064-HP can be placed safely without clipping or exceeding the intensity limit with 1W power.
• All solutions in order of sensitivity are plotted here with details of lens choice and positions. In total 7 solutions were found which are stored in BestSolutions.mat.

Analysis & Data

Wed Jan 6 10:00:35 2021: This analysis was wrong. See SUS_Lab/1887.