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 (∼100 fs) when the pulse peak intensity is less than 5×10¹¹ 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.
© 2005 Optical Society of America
Shuyan Zhang, Qiguang Yang, and Gunter Lüpke, "Spatial beam shaping of ultrashort laser pulses: theory and experiment," Appl. Opt. 44, 5818-5823 (2005)