Discharge electrodes include a cathode and an anode. The anode is disposed to face the cathode in a discharge direction perpendicular to a longitudinal direction of the cathode, and includes an electrode base 1, and a coating layer that covers a portion of a surface of the electrode base. First corners in a cross section perpendicular to the longitudinal direction connect first straight sections formed of first side surfaces that are side surfaces of the electrode base to a first curved section formed of a first discharge surface that is a discharge surface of the electrode base. The first corners are closer to the cathode in the discharge direction than second corners connecting second straight sections formed of second side surfaces that are side surfaces of the coating layer to a second curved section formed of a second discharge surface that is a discharge surface of the coating layer.

A laser device may include a laser resonator; a chamber arranged on an optical path of the laser resonator; a pair of electrodes arranged in the chamber; a power source applying a voltage to the electrodes; a storage unit storing a voltage value; and a control unit configured to set an application voltage value of the voltage applied to the electrodes as setting the application voltage value for outputting a pulse whose pulse number is equal to or larger than 1 and smaller than i based on the voltage command value and the voltage value stored in the storage unit, and setting the application voltage for outputting a pulse whose pulse number is equal to or larger than i and smaller than j based on the voltage command value and an offset value corresponding to the voltage command value, where i>1 and j>i.

A gas laser apparatus according to an aspect of the present disclosure includes a main discharge circuit that supplies main discharge voltage that causes main discharge to a pair of main discharge electrodes, and a pre-ionization circuit that supplies pre-ionization voltage that causes corona discharge to a pre-ionization electrode. The main discharge circuit includes a step-up pulse transformer, a main capacitor and a switch connected to a primary side of the step-up pulse transformer, a first power source that charges the main capacitor, a first capacitor connected in parallel to a secondary side of the step-up pulse transformer, a first magnetic switch connected to the first capacitor, and a peaking capacitor connected in parallel to the first capacitor through the first magnetic switch and to the main discharge electrodes. An interval between start timings of the corona discharge and the main discharge is 30 ns to 60 ns inclusive.

A laser system for amplifying laser light generated from a laser light source and emitting the laser light includes an optical element in an optical path of the laser light and transmits the laser light, a control device to control power to be supplied to the laser system, an imager to capture an image of the optical element, and an image processing circuitry to process the image of the optical element captured by the imager. The image processing circuitry in which reference images of the optical element corresponding to power information relating to the power are prepared in advance includes a comparison unit to compare a captured image of the optical element captured by the imager with a reference image selected by a reference image selection unit, the reference image corresponding to the power information at a time of image capturing by the imager.

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.

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.

A gas laser apparatus includes: a magnetic bearing including an electromagnet capable of controlling a magnetic force, and configured to rotatably support a rotary shaft of a fan in a magnetically levitated state by the magnetic force, the fan being configured to supply a laser gas; an electromagnet control unit configured to control the magnetic force of the electromagnet based on displacement of a levitated position of the rotary shaft and adjust the levitated position; a motor configured to generate torque for rotating the fan; a magnetic coupling configured to couple the rotary shaft and a drive shaft of a motor with a magnetic attractive force and transmit the torque of the motor to the rotary shaft; an attractive force estimating sensor configured to detect a parameter that enables an attractive force of the magnetic coupling to be estimated; an attractive force measuring unit configured to measure the attractive force of the magnetic coupling based on the detected parameter; and a correction unit configured to correct the magnetic force of the electromagnet according to a variation in the attractive force measured by the attractive force measuring unit.

A gas laser apparatus includes: a magnetic bearing including an electromagnet capable of controlling a magnetic force, and configured to rotatably support a rotary shaft of a fan in a magnetically levitated state by the magnetic force, the fan being configured to supply a laser gas; an electromagnet control unit configured to control the magnetic force of the electromagnet based on displacement of a levitated position of the rotary shaft and adjust the levitated position; a motor configured to generate torque for rotating the fan; a magnetic coupling configured to couple the rotary shaft and a drive shaft of a motor with a magnetic attractive force and transmit the torque of the motor to the rotary shaft; an attractive force estimating sensor configured to detect a parameter that enables an attractive force of the magnetic coupling to be estimated; an attractive force measuring unit configured to measure the attractive force of the magnetic coupling based on the detected parameter; and a correction unit configured to correct the magnetic force of the electromagnet according to a variation in the attractive force measured by the attractive force measuring unit.

An apparatus includes: a gas maintenance system having a gas supply system fluidly connected to one or more gas discharge chambers; a detection apparatus fluidly connected to each gas discharge chamber; and a control system connected to the gas maintenance system and the detection apparatus. The detection apparatus includes: a vessel defining a reaction cavity that houses a metal oxide and is fluidly connected to the gas discharge chamber for receiving mixed gas including fluorine from the gas discharge chamber in the reaction cavity, the vessel enabling a reaction between the fluorine of the received mixed gas and the metal oxide to form a new gas mixture including oxygen; and an oxygen sensor fluidly connected to the new gas mixture to sense an amount of oxygen within the new gas mixture. The control system is configured to estimate a concentration of fluorine in the received mixed gas.

An apparatus includes: a gas maintenance system having a gas supply system fluidly connected to one or more gas discharge chambers; a detection apparatus fluidly connected to each gas discharge chamber; and a control system connected to the gas maintenance system and the detection apparatus. The detection apparatus includes: a vessel defining a reaction cavity that houses a metal oxide and is fluidly connected to the gas discharge chamber for receiving mixed gas including fluorine from the gas discharge chamber in the reaction cavity, the vessel enabling a reaction between the fluorine of the received mixed gas and the metal oxide to form a new gas mixture including oxygen; and an oxygen sensor fluidly connected to the new gas mixture to sense an amount of oxygen within the new gas mixture. The control system is configured to estimate a concentration of fluorine in the received mixed gas.