Abstract: A phase-conjugated Q-switched laser resonator. The resonator contains a laser active material and a polarizer/quarter-wave plate combination in a starter cavity. The polarizer optically couples one plane of polarization of laser radiation into a side arm containing a self-switching stimulated scattering phase-conjugate mirror.

Abstract: Angular movements of an object are detected using a laser beam reflected m a mirror on the object and focussed on the edge of a straight edge in front of a photodetector. The same laser beam may be used with the same photodetector to simultaneously or separately form a Michaelson interferometer for detecting linear movements of the object. Alternatively, two photodetectors may be used such that linear and the combination of rotational and angular movements are detected simultaneously, and three photodetectors are used to detect simultaneously linear, rotational, and the combination of linear and rotational movements. In all embodiments, a telescope multiplies mirror movement by the magnifying power of the telescope.

Abstract: A multiple reflections interferometer (MRI) which eliminates the normal angle of incidence requirement of other interferometers, such as the standard Michelson interferometer (SMI), and allows convenient choices of interferometric sensitivities, such as exactly 100 nanometers per cycle or 10 nanometers per cycle using a helium-neon laser. The MRI has the mirror that usually receives the normal incidence beam replaced by a two-mirror wedge produce multiple reflections therein to provide greater displacement sensitivities.