Compact femtosecond autocorrelator based on a swinging birefringent plate

Summary form only given. A new method to introduce a variable temporal delay of ultra-short light pulses with the help of a birefringent crystal is proposed and studied. Variation in the propagation velocity difference between the ordinary and extraordinary waves in a birefringent crystal that comes from change of crystal´s optical axis orientation with respect to incident light beam makes it possible to implement a compact delay line for ultra-short pulses, based on a swinging birefringent plate. Variation of temporal delay /spl Delta/t between the ordinary and extraordinary components of light pulse inside a birefringent crystal of thickness d when it gets turned by a small angle /spl Omega/ with respect to Z axis is given by the following linear approximation: /spl Delta/t=/spl plusmn/d/cc[sin(2/spl theta/)(1/n/sub c//sup 2/$ -1/n/sub o//sup 2/)/2(sin/sup 2/(/spl theta/)/n/sub o//sup 2/(/spl theta/)/n/sub c//sup 2/)/sup -3/2/]/spl Omega/ where c is the speed of light in vacuum, n/sub o/, n/sub e/ are the principal refractive indices of the ordinary and extraordinary waves, /spl theta/ is the angle between the ordinary wave vector and the principal plane of the crystal.