A method is performed for scheduling a calibration relating to an optical device in a light source. The method can be performed by a calibration system including a calibration apparatus and a prediction controller. The method includes: receiving a property associated with the optical device while the optical device is being calibrated; calculating a current degradation metric based at least on the optical device property, the degradation metric modeling behavior of the optical device; estimating when a degradation of the optical device would exceed a threshold based on the current degradation metric; and scheduling a calibration of the optical device based at least in part on the estimate of optical device degradation.

A system includes a laser source operable to provide a laser beam, a laser amplifier having a gain medium operable to provide energy to the laser beam when the laser beam passes through the laser amplifier, and a residual gain monitor operable to provide a probe beam and operable to derive a residual gain of the laser amplifier from the probe beam when the probe beam passes through the laser amplifier while being offset from the laser beam in time or in path.

A system includes a laser source operable to provide a laser beam, a laser amplifier having a gain medium operable to provide energy to the laser beam when the laser beam passes through the laser amplifier, and a residual gain monitor operable to provide a probe beam and operable to derive a residual gain of the laser amplifier from the probe beam when the probe beam passes through the laser amplifier while being offset from the laser beam in time or in path.

Methods and apparatus for controlling laser firing timing and hence bandwidth in a laser capable of operating at any one of multiple repetition rates.

Methods and apparatus for controlling laser firing timing and hence bandwidth in a laser capable of operating at any one of multiple repetition rates.

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 control method for stabilizing excimer laser pulse energy includes: obtaining a measured energy value of the n-th pulse in a pulse sequence; calculating the difference between the measured energy value and the preset energy value; taking the z-th pulse of the sequence as a demarcation point, when n is a positive integer less than z, the discharge voltage value of the next pulse is calculated according to a first mathematical model, and when n is an integer greater than z−1, the discharge voltage value of the next pulse is calculated according to a second mathematical model; and the next pulse is generated according to the discharge voltage value. A control system based on the control method includes: a high-voltage discharge module, a laser cavity, a laser parameter measurement module, and an energy stability controller.

A laser system includes an oscillation stage laser configured to output first laser light, and an amplification stage laser configured to amplify the first laser light and output second laser light. A control method of the laser system includes determining a condition under which an amplification characteristic of the amplification stage laser changes, acquiring relationship between pulse energy of the first laser light and a parameter of the second laser light when the condition is determined to be satisfied, and setting target pulse energy of the first laser light based on the relationship.

A laser system includes an oscillation stage laser configured to output first laser light, and an amplification stage laser configured to amplify the first laser light and output second laser light. A control method of the laser system includes determining a condition under which an amplification characteristic of the amplification stage laser changes, acquiring relationship between pulse energy of the first laser light and a parameter of the second laser light when the condition is determined to be satisfied, and setting target pulse energy of the first laser light based on the relationship.

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.