Self-diffraction: A new method for characterization of ultrashort laser pulses

Abstract

We show that the duration and coherence time of ultrashort laser pulses can be measured by a transient grating technique. In the method, a self-diffracted signal is recorded as a function of delay between two identical pulses that induce the grating in an absorbing medium. An integrated-intensity grating analysis that considers fourth-order partial-coherence effects describes the diffraction efficiency of the grating. This method, which is easily implemented, inexpensive, and can be used at any wavelength, is demonstrated with low-repetition-rate picosecond lasers.