CHIRP PULSE AMPLIFIER, AND AMPLIFICATION METHOD

PROBLEM TO BE SOLVED: To provide a chirp pulse amplifier which suppresses variation in spatial light intensity distribution or spreading angle of an amplified laser pulse, without using a polarized beam splitter. SOLUTION: A pulse extender chirps a laser pulse to extend a pulse width. The laser pulse chirped by the pulse extender is made incident to a pulse compressor. The pulse compressor includes a diffraction grating, and the pulse width is compressed by utilizing the difference in optical path lengths of wavelength components polarized by the diffraction grating. A polarization direction varying means for varying a polarization direction of the laser pulse is disposed between the pulse extender and the pulse compressor. An optical amplifier is disposed between the pulse extender and the pulse compressor. COPYRIGHT: (C)2008,JPO&INPIT