Features of a phase-only shaper set for a long rectangular pulse

S. Cialdi, I. Boscolo, A. Flacco
2004 Journal of the Optical Society of America. B, Optical physics  
The generation of electron pulses of high peak current and low emittance in a 3-GHz radio-frequency electron gun requires the illumination of the photocathode by a rectangular-shaped 10-ps light beam with a rise time of less than 1 ps. The generation of this kind of laser pulse needs the insertion of a programmable pulse shaper into a femtosecond laser system. The shaping system that we discuss is a spectral phase-only filter. A genetic algorithm, in conjunction with a proper cost function, is
more » ... cost function, is used to determine the phase filter function for the desired square-pulse generation. Simulations show that the system is highly sensitive to the properties of the input signal and to alignment. Third-harmonic generation, as required by photoemission, leads to some relaxation in the settings of the system.
doi:10.1364/josab.21.001693 fatcat:hnzkhdbgoracfjzuousdkzrhxq