DISPERSIVE OPTICAL DELAY LINE AND UTILIZATION OF SAID DELAY LINE FOR COMPRESSION/EXTENSION OF LASER PULSE

摘要

PURPOSE: To provide an optical delay line with small linear errors in a wide band. CONSTITUTION: These distributed optical delay lines for frequency modulated light wave pulses, especially laser waves, are parallel to each other, separated for a distance (d), provided with a refractive index N and localized with a pitch (a) on the surface of a material transparent to light waves. A first optical grating and a second optical grating are provided. Incident waves are diffracted at an angle ' larger than the limit angle of refraction by being transmitted through the first and second optical gratings and an emission angle from the second grating is also '. The values of parameters N, ', (a) and (d) are selected so as to make the fluctuation of delay time R by the delay line passing of pulses correspond to the modulation band width f of the pulses inside a quasi-linear area. The delay line is applied to compression/expansion for obtaining high output laser pulses or extremely short laser pulses.