John M. Tracy

Possibility of relative position sensing by using double phase-conjugate resonators

Abstract We propose and analyze the possibility of using double phase-conjugate resonators as linear relative-position sensors. Such position sensors are linear analogs to ring laser gyros, but require optical phase conjugation for their operation. In principle,a position sensor as proposed allows measurement of the linear position of a platform relative to an inertial frame in which an optical standing wave has been established. The relative position sensing is based on the inertial nature of the electromagnetic radiation.

Theory of dispersive birefringent filters

Polarization interference filters that employ crystals with a strong dispersion of birefringence as the wave plates can provide a very narrow band pass width by using very thin crystal plates. If in addition, the birefringence is small, this filter can accommodate a very wide field-of-view. It is noted, in particular, that CdS exhibits a strong dispersion in the spectral regime between 5200 Å and 5400 Å, with a rate of dispersion that could provide a passband of only 1 Å with a filter structure of several millimeters thick. This paper investigates the properties of these filters. The results are presented and discussed.

Birefringence of Znx Cd 1− x S near the isotropic point

The birefringence of the mixed crystal Zn0.14Cd0.86S has been measured near its isotropic point and found to be highly dispersive. The region of strong dispersion shifts to shorter wavelengths than observed in pure CdS, and its magnitude near the isotropic point is larger. These results are highly significant for the development of narrowband dispersive birefringent filters in the blue-green region of the spectrum.