A small rugged interferometer was required for measuring the depletion zones generated in a protein crystal growth experiment. The exploration for an optimum solution yielded an instrument that uses solid optical design techniques, where air is removed from the optical path and replaced with 'solid air' or glass. The interferometer is a Mach-Zehnder configuration with the reference and test arms separated as orthogonal polarization states with a polarization beam splitting cube (PBSC), then recombined by another PBSC, maintaining the orthogonality of the reference and test beam polarizations. An off-the-shelf liquid crystal variable phase plate was sufficient to produce the necessary 2(pi) phase shift. The device was built and tested and shoed excellent performance. The spatial resolution of the interferometer is limited only by the 0.011mm pixels at the 5 by 5 mm detector and the imager is operating at telecentric 1:1 conjugates. Phase resolution, using the Hariharan 5-step algorithm, is measured to be better than (lambda) /50. In this paper, calibration test results are presented and future upgrades are outlined.

Date Published: 25 October 1999
PDF: 8 pages
Proc. SPIE 3754, Polarization: Measurement, Analysis, and Remote Sensing II, (25 October 1999); doi: 10.1117/12.366328

Published in SPIE Proceedings Vol. 3754:
Polarization: Measurement, Analysis, and Remote Sensing II
Dennis H. Goldstein; David B. Chenault, Editor(s)