Continuous waveform variable true-time delay by optical coherent transients

We experimentally demonstrate for the first time variable delay of a contin uous optical waveform using a spectral-spatial grating programmed with two, temporally overlapping frequency chirped pulses. Variation in the programm ed time delay is achieved from 375 ns to 625 ns by frequency shifting of th e chirped programming pulses. A box input beam geometry is used so that the emitted output signal is phase matched and isolated from all the input pul ses. Experiments were performed in Tm3+:YAG at 5 K on the transition at 793 nm. (C) 2000 Published by Elsevier Science B.V. All rights reserved.