Focusing and deflection of optical beams by cylindrical mirrors.

An optical system incorporating two closely spaced cylindrical mirrors is described. By properly orienting the mirrors in space, an incident beam can be focused at any desired point within a large volume. This simple periscopic system, which provides variable focal lengths and deflection angles, is applicable to optical or millimeter wave transmission systems lying along irregular paths. A paraxial ray theory of the system is given, as well as experimental results.

Measurement of the laser frequency control characteristics of piezoelectric transducers.

The frequency of a laser can be controlled by mounting one of the resonator mirrors on a piezoelectric transducer and applying a control voltage to the transducer. The proper design of an automatic frequency control system requires more information about the transducer's dynamic behavior than is available from manufacturer's data. This dynamic behavior can be measured by applying an alternating voltage to such a transducer in an operating laser and using an optical heterodyne FM receiver to measure the frequency modulation produced. Comparison of the control voltage applied to the transducer with the output of the FM demodulator can yield useful information about the dynamic response of the transducer. Instrumentation used to make such measurements is described and some typical data are presented.