Abstract: A laser output device includes: a laser oscillator for oscillating a source laser pulse; a pulse extender for temporally extending the source laser pulse oscillated by the laser oscillator; an amplifier for amplifying the laser pulse temporally extended by the pulse extender; the laser pulse filter for filtering a pre-pulse and a post-pulse contained in the amplified laser pulse; and a pulse compressor for temporally compressing the laser pulse which has passed through the laser pulse filter.

Abstract: A laser amplifier capable of achieving a high output by offsetting distortion of an amplified laser beam. The laser amplifier includes: first and second amplification media which amplify a penetrating laser beam; a pre-compensation lens unit which pre-compensates for a laser beam irradiated to the first amplification medium so as to offset a thermal lensing effect generated in the first amplification medium and the second amplification medium; a first polarizing and penetrating mirror inclined to the laser beam irradiated to a front end of the first amplification medium and allowing a laser beam that vibrates in a specific direction to penetrate and reflecting a laser beam that vibrates in another direction; a polarization conversion plate provided at a rear side of the second amplification medium and changing a vibration direction of the laser beam penetrating the second amplification medium; and a first reflection mirror for reflecting a laser beam.