Narrow band excimer laser

摘要

A narrow band excimer laser capable of easily adjusting the rotation of the laser beam by an image rotator provided between a laser chamber and a grating and on the laser beam optical axis. The image rotator is supported with freedom of rotation on the laser beam optical axis and rotates the laser beam about the optical axis so that the plane containing the direction in which the width of the laser beam incident upon the beam expander is narrower is parallel with the plane containing the beam-expansion direction of the beam expander, and the beam expansion direction of the laser beam incident upon the grating is perpendicular to the direction of the grooves of the grating. With this arrangement, a laser beam of narrowed bandwidth can be obtained with high efficiency.