title: Spatial beam shaping of ultrashort laser pulses: theory and experiment.
abstract: We studied the spatial intensity profile of an ultrashort laser pulse passing through a laser beam shaping system, which uses diffractive optical elements to reshape a Gaussian beam profile into a flat-topped distribution. Both dispersion and nonlinear self-phase modulation are included in the theoretical model. Our calculation shows that this system works well for ultrashort pulses (approximately 100 fs) when the pulse peak intensity is less than 5 x 10(11) W/cm2. Experimental results are presented for 136 fs pulses at 800 nm wavelength from a Ti:sapphire laser with a 6 nJ pulse energy. We also studied the effects of lateral misalignment, beam-size deviation, and defocusing on the energy fluence profile.
authors.affiliation: Department of Applied Science, The College of William and Mary, Williamsburg, Virginia 23187, USA. sxzhang@wm.edu
authors.forename: Shuyan
authors.initials: S
authors.lastname: Zhang
authors.forename: Qiguang
authors.initials: Q
authors.lastname: Yang
authors.forename: Gunter
authors.initials: G
authors.lastname: Lüpke