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 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.

Features of a phase-only shaper set for a long rectangular pulse / S. Cialdi, I. Boscolo, A. Flacco. - In: JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. B, OPTICAL PHYSICS. - ISSN 0740-3224. - 21:9(2004), pp. 1693-1698.

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

S. Cialdi
Primo
;
I. Boscolo
Secondo
;
A. Flacco
Ultimo
2004

Abstract

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 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.
Electron pulses ; low emittance ; rectangular beam ; laser ; pulse shaping
Settore FIS/01 - Fisica Sperimentale
2004
Article (author)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/16800
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