Arbitrary shaping of amplified femtosecond pulses with phase-only filters

Summary form only given. Fourier-transform synthesis of femtosecond laser pulses is opening up new application fields including mode-selective excitation of coherent phonons and generation of THz radiation from a semiconductor quantum well. Some applications, such as the coherent control of chemical reactions and the efficient generation of electrons in an RF-gun, need amplified and arbitrarily shaped femtosecond laser pulses. When we want such pulses, we should place a pulse shaping apparatus, which consists of a modulating devise, a grating pair, and a lens pair, between an oscillator and an amplifier to avoid damages to a modulation device. In order to obtain arbitrarily shaped femtosecond laser pulses, we may use amplitude-phase filters or a phase-only filter. Amplitude modulation of laser pulses before the chirped pulse amplification may cause damages of optical elements in a regenerative amplifier especially for a longer shaped pulse. Hence, in this presentation, we show the results with a phase-only filter, which does not cause damages in a process of the chirped pulse amplification.