An optical path cover is located on an optical path through which beam light travels. The optical path cover includes a cylindrical portion through which the beam light is capable of passing. A plurality of protruding portions are formed on inner walls of the cylindrical portion, the inner walls facing toward a side of an optical axis of the beam light. The protruding portions, each of which has a convex shape in cross-section taken perpendicularly to the optical axis, are arranged next to each other with the convex shape facing toward the side of the optical axis. Each of the protruding portions has an elongated shape extending along the optical axis.

An optical path cover is located on an optical path through which beam light travels. The optical path cover includes a cylindrical portion through which the beam light is capable of passing. A plurality of protruding portions are formed on inner walls of the cylindrical portion, the inner walls facing toward a side of an optical axis of the beam light. The protruding portions, each of which has a convex shape in cross-section taken perpendicularly to the optical axis, are arranged next to each other with the convex shape facing toward the side of the optical axis. Each of the protruding portions has an elongated shape extending along the optical axis.

An optical path cover is located on an optical path through which beam light travels. The optical path cover includes a cylindrical portion through which the beam light is capable of passing. A plurality of protruding portions are formed on inner walls of the cylindrical portion, the inner walls facing toward a side of an optical axis of the beam light. The protruding portions, each of which has a convex shape in cross-section taken perpendicularly to the optical axis, are arranged next to each other with the convex shape facing toward the side of the optical axis. Each of the protruding portions has an elongated shape extending along the optical axis.

An optical path cover is located on an optical path through which beam light travels. The optical path cover includes a cylindrical portion through which the beam light is capable of passing. A plurality of protruding portions are formed on inner walls of the cylindrical portion, the inner walls facing toward a side of an optical axis of the beam light. The protruding portions, each of which has a convex shape in cross-section taken perpendicularly to the optical axis, are arranged next to each other with the convex shape facing toward the side of the optical axis. Each of the protruding portions has an elongated shape extending along the optical axis.

A line narrowing module includes a prism including an entrance side surface that light enters, an exit side surface from which the light is emitted, and a bottom surface, and configured to wavelength-disperse the light having entered the entrance side surface and to emit the light from the exit side surface; a holder portion having a stationary surface on which the bottom surface of the prism is secured; a rotary mechanism portion including a rotary stage on which the holder portion is secured, the rotary stage being configured to rotate the prism around an axis perpendicular to a dispersion plane of the light emitted from the prism; a drive unit configured to rotate the rotary stage; and a grating configured to reflect the light emitted from the prism, centroids of the prism, the holder portion, and the rotary stage being located on the axis.

A laser chamber apparatus may include a pipe, an inner electrode extending along a longitudinal direction of the pipe and disposed in a through hole in the pipe, an outer electrode including a contact plate extending along the longitudinal direction of the pipe and being in contact with an outer circumferential surface of the pipe and a ladder section formed of bar members each having one end connected to the contact plate and juxtaposed along a longitudinal direction of the contact plate, and a leaf spring extending along the longitudinal direction of the pipe and configured to press the outer electrode against the pipe. The leaf spring may include leaf spring pieces separated by slits, and the leaf spring pieces may each include a bent section bent along the edge and are configured to press the bar members in a position shifted from the bent sections toward the edge.

The present disclosure relates to a laser system/package that is configured to enable the detection of a change in an optical device that is intended to alter light emitted from the laser. The system is designed to measure an electric or magnetic field that is affected by the optical device. As a result, changes in the optical device, for example because the optical device has been damaged or dislodged or removed, should be detected by a corresponding change in the electric or magnetic field.

A gas laser apparatus includes a chamber; a window provided in the chamber; an optical path tube connected to the chamber; a gas supply port that supplies a purge gas into the optical path tube; an exhaust port that exhausts a gas in the optical path tube; and a control unit, the exhaust port including a main exhaust port provided in the optical path tube, and an auxiliary exhaust port provided in the optical path tube upstream of a flow of the gas in the optical path tube with respect to positions of the window and the main exhaust port, the control unit causing the gas to be exhausted through the main exhaust port before a laser beam is emitted from the chamber and causing the gas to be exhausted through the auxiliary exhaust port in at least a partial period when the laser beam is emitted.

A gas laser apparatus includes a chamber; a window provided in the chamber; an optical path tube connected to the chamber; a gas supply port that supplies a purge gas into the optical path tube; an exhaust port that exhausts a gas in the optical path tube; and a control unit, the exhaust port including a main exhaust port provided in the optical path tube, and an auxiliary exhaust port provided in the optical path tube upstream of a flow of the gas in the optical path tube with respect to positions of the window and the main exhaust port, the control unit causing the gas to be exhausted through the main exhaust port before a laser beam is emitted from the chamber and causing the gas to be exhausted through the auxiliary exhaust port in at least a partial period when the laser beam is emitted.

A laser oscillator unit includes an amplification unit configured to amplify laser light and emit amplified laser light from an emitting portion; a case covering the amplification unit; and an outer support mechanism and an inner support mechanism provided on the case. The case is formed with a window portion. An outer movable leg allows the case to slide in a radial direction around an outer fixed leg. An inner movable leg allows the amplification unit to slide in the radial direction around an inner fixed leg. A straight line passing through a center of the outer fixed leg and a center of the inner fixed leg intersects with a straight line passing through the emitting portion and the window, and a laser optical axis emitted from the emitting portion and a laser optical axis emitted from the window portion coincide with each other.