Programmable shaping of a subterawatt, femtosecond laser pulse by modulating the spectral phase of the preamplified pulse

Shaping the temporal profile of subterawatt optical pulses with a femtosecond duration is demonstrated with the help of a programmable pulse shaper, which is based on a liquid–crystal spatial light modulator. For safe operation, we place the pulse shaper between regenerative and multipass amplifiers. We generate double pulses, whose respective component pulses have 0.27-TW peak power and 74-fs duration. The possibility of variously-shaped multiterawatt pulses is also discussed.