Other

Leland Stanford Junior University

Theodor W Hansch

John L Hall

Bernard J Couillaud

An external laser frequency stabilizer combines an acousto-optic frequency shifter and a fast electro-optic phase modulator. A compensating electronic delay line in a crossover network provides a near-ideal transducer response while keeping the voltage across the electro-optic crystal away from the amplifier limits.

External laser frequency stabilizer

Herein is disclosed a method of and apparatus for measuring optical frequency variations wherein linearly-polarized incident light generated by a tunable laser or the like is delivered to a passive resonant cavity incorporating a linear polarizer such as a Brewster plate so that the reflected light acquires a frequency-dependent elliptical polarization which can be detected by a simple polarization analyzer providing a signal correlated with the frequency variation of the laser. Such signal can be utilized as a feedback error signal to stabilize the laser frequency, or to adjust the cavity resonance. If the cavity is tunable, tuning thereof will in turn provide a precision method for tuning of the laser itself.

Method of and apparatus for measuring optical frequency variations

The invention constitutes a method of and apparatus for measuring the absolute wavelength of a source of unknown frequency radiation through directing radiant energy of known frequency against a diffraction grating of predetermined pattern so as to image a calibrated scale on a suitable screen or the like, and then directing the radiant energy from the unknown frequency source along the same path to the diffraction grating and onto the screen, where a visually available easy-to-read measurement of the wavelength appears.

Growing community of inventors

Palo Alto, CA, United States of America

Theodor W Hansch