DIFFRACTION GRATING FOR LASER PULSE COMPRESSION AND LASER DEVICE

摘要

A pulse compressor for compressing a laser pulse in a laser device using a chirped pulse amplification method includes two identically shaped diffraction gratings arranged parallel to each other with their respective grating surfaces facing each other and a total reflection mirror for receiving a laser pulse through the diffraction grating and returning it back to the same gratings. Each diffraction grating is a reflective blazed diffraction grating having grooves with a sawtooth-shaped section covered with a reflective Au coating on their surface, with the blaze angle determined so that, at the wavelength of the laser pulse to be used, the incident angle of a laser pulse entering the pulse compressor and first order diffracted light form a relationship of mirror reflection with the groove slope and so that a predetermined level of diffraction efficiency is obtained. Since the laser pulse impinges on the grating at substantially right angles to the groove slope, a high level of damage threshold is obtained and a high-power laser pulse can be generated.

主权项

1. A diffraction grating to be used in a pulse compressor including two identically shaped diffraction gratings arranged parallel to each other with their respective grating surfaces facing each other in a laser device using a chirped pulse amplification method, wherein:
the diffraction grating is a reflective blazed diffraction grating having grooves with a sawtooth-shaped section covered with a reflective metallic coating at least on their surface, the diffraction grating having a blaze angle determined so that, at a wavelength of a laser pulse to be used, an incident angle of an incoming laser pulse and first order diffracted light form a relationship of mirror reflection with a groove slope, and a predetermined level of diffraction efficiency is obtained.