title: Splitting of femtosecond laser pulses by using a Dammann grating and compensation gratings.
abstract: When a Dammann grating is used to split a beam of femtosecond laser pulses into multiple equal-intensity beams, chromatic dispersion will occur in beams of each order of diffraction and with different scale of angular dispersion because the incident ultrashort pulse contains a broad range of spectral bandwidths. We propose a novel method in which the angular dispersion can be compensated by positioning an m-time-density grating to collimate the mth-order beam that has been split, producing an array of beams that are free of angular dispersion. The increased width of the compensated output pulses and the spectral walk-off effect are discussed. We have verified this approach theoretically and validated it through experiments. It should be highly interesting in practical applications of splitting femtosecond laser pulses for pulse-width measurement, pump-probe measurement, and micromachining at multiple points.
authors.affiliation: Shanghai Institute of Optics and Fine Mechanics, Academia Sinica, P.O. Box 800-211, Shanghai 201800, China.
authors.forename: Guowei
authors.initials: G
authors.lastname: Li
authors.forename: Changhe
authors.initials: C
authors.lastname: Zhou
authors.forename: Enwen
authors.initials: E
authors.lastname: Dai