A gas laser apparatus may include a chamber filled with a laser gas; a window provided in the chamber and through which a laser beam passes; an optical path tube connected to the chamber to surround a position of the window in the chamber; a heated gas supply port configured to supply a heated purge gas into a closed space including a space in the optical path tube; and an exhaust port configured to exhaust a gas in the closed space.

An optical element for a deep-ultraviolet light source includes a crystalline substrate; a coating on an exterior surface of the crystalline substrate, the coating having a thickness along a direction that extends away from the exterior surface; and a structure on and/or in the coating, the structure including a plurality of features that extend away from the crystalline substrate along the direction. The features include an amorphous dielectric material and are arranged such that an index of refraction of the structure varies along the direction.

An optical element for a deep-ultraviolet light source includes a crystalline substrate; a coating on an exterior surface of the crystalline substrate, the coating having a thickness along a direction that extends away from the exterior surface; and a structure on and/or in the coating, the structure including a plurality of features that extend away from the crystalline substrate along the direction. The features include an amorphous dielectric material and are arranged such that an index of refraction of the structure varies along the direction.

A method for forming in particular reflection-reducing nanostructures (5) on a preferably polished surface (3) of a crystalline, in particular ionic, substrate (1) for transmission of radiation in the FUV/VUV wavelength range. The method includes: providing a surface (3, 7), which surface is not oriented along a lattice plane having a minimum surface energy, on the substrate (1) or on a layer (6) applied to the substrate (1) by a coating method, in particular vacuum vapor deposition, and introducing an energy input (E) into the surface (7) for rearranging the surface (7) to form the nanostructures (5), wherein the energy input (E) is generated by irradiating the surface (7) with electromagnetic radiation (4). Also, an optical element for transmission of radiation in the FUV/VUV wavelength range.

A laser crystallization method includes exciting gas medium in an airtight container to generate laser beams; amplifying the laser beams by reflecting the laser beams between a high reflection mirror and a low reflection mirror respectively disposed facing opposite end portions of the airtight container, wherein a first transparent window and a second transparent window are fixed to respective end portions of the airtight container, and outputting the amplified laser beams; and disposing a cleaning mirror in a path of the laser beams that have propagated through the second transparent window.

A light source apparatus includes an airtight container having a hemispherical or semielliptical first curved portion configured to receive laser light, a hemispherical or semielliptical second curved portion opposite to the first curved portion, and a cylindrical portion connecting the first curved portion and the second curved portion; assist gas sealed in the airtight container; and a light source configured to irradiate laser light to the first curved portion from outside of the airtight container.

A light source apparatus includes an airtight container having a hemispherical or semielliptical first curved portion configured to receive laser light, a hemispherical or semielliptical second curved portion opposite to the first curved portion, and a cylindrical portion connecting the first curved portion and the second curved portion; assist gas sealed in the airtight container; and a light source configured to irradiate laser light to the first curved portion from outside of the airtight container.

The present disclosure relates to systems, methods, and computer readable media for modeling thermal effects within a multi-laser device. For example, systems described herein may include a plurality of laser devices that output energy streams having corresponding operating windows. One or more systems described herein may include a set of accumulators for tracking quantities of energy samples within operating windows and populating a queue representative of the tracked quantities. One or more systems described herein may additionally include filters and a summing module for determining temperature values for operating windows and synchronizing the temperature values with one another to determine an accurate system temperature for the multi-laser device. The features described herein facilitate synchronization of data for corresponding operating windows to provide an accurate determination of system temperature based on a combination of self-heating and crosstalk effects between multiple laser devices.

A system for removing particulate matter from the gas in a gas discharge laser includes one or more nonwoven screens which are optimized for, among others, manufacturability and feature integration. The nonwoven screens are configured for precisely directing the flow to optimize the separation of particles from the gas flow and provide sufficient surface area for improved dust adherence.

A laser apparatus including an optical element made of a CaF.sub.2 crystal and configured to transmit an ultraviolet laser beam obliquely incident on one surface of the optical element, the electric field axis of the P-polarized component of the laser beam propagating through the optical element coinciding with one axis contained in <111> of the CaF.sub.2 crystal, with the P-polarized component defined with respect to the one surface. A method for manufacturing an optical element, the method including causing a seed CaF.sub.2 crystal to undergo crystal growth along one axis contained in <111> to form an ingot, setting a cutting axis to be an axis inclining by an angle within 14.185 with respect to the crystal growth direction toward the direction of another axis contained in <111>, which differs from the crystal growth direction, and cutting the ingot along a plane perpendicular to the cutting axis.