Scanning Polarizing Microscope
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
The measurement of phase difference between horizontal and vertical polarizations of a laser beam both before and after interacting with a specimen in a polarization microscope permits significant improvement in detection sensitivity. The heterodyne detection system is shown in the schematic illustration. Light from a Zeeman split, frequency stabilized, single-mode laser 1 provides right and left circular polarizations at frequencies of wo + wm and wo- wm, respectively, where wo is the optical frequency and wm is determined by the axial magnetic field applied to the laser. A half-wave plate on the laser converts the circular polarizations to horizontal and vertical polarizations. Output light passes through Bragg cell 2 that upshifts the light frequency and blocks reflected light.