Chromatic-distortion compensation in splitting and focusing of femtosecond pulses by use of a pair of diffractive optical elements.

We propose a simple optical system to compensate for chromatic distortion that occurs during fan-out of femtosecond pulses by diffractive optics. The proposed system comprises a pair of diffractive elements, one for splitting an incoming pulse and the other for focusing the split pulses. With an appropriate separation between the elements, chromatic distortion resulting from the spectral bandwidth of a femtosecond pulse is removed, and an array of focused pulses with the same dimensions can be obtained. The theory has been verified through optical and processing experiments with 100-fs, 800-nm pulses.