Analysis of compression of frequency chirped optical pulses by a strongly dispersive grating pair

An optical pulse compression medium formed by two parallel gratings can be strongly dispersive if the diffracted beam emerges at grazing angle from the surface of the first grating. Strong dispersion makes possible temporal compression of broad incident pulses. However, sufficiently strong dispersion is accompanied by a nonlinear variation of group delay with carrier frequency, which will cause the envelope of the compressed pulse to be distorted and limit the minimum attainable pulse width. Strong dispersion as a limiting influence upon compression of linearly chirped pulses is examined for the grating pair at several laser wavelengths. Specific examples are discussed for the compression of CO(2) laser pulses at 10.6-microm wavelength.