An assembly (10) for generating a laser beam (12) includes a beam steering assembly (18); a laser assembly (16) that is tunable over a tunable range; and a controller (20). The laser assembly (16) generates a laser beam (12) that is directed at the beam steering assembly (18). The controller (20) dynamically controls the beam steering assembly (18) to dynamically steer the laser beam (12) as the laser assembly (16) is tuned over at least a portion of the tunable range. As a result thereof, the laser beam (12) is actively steered along a desired beam path (12A) while the wavelength of the laser beam (12) is varied.

Provided is a light source apparatus and an electrode design for use in a discharge chamber of the light source apparatus. The discharge chamber is configured to hold a gas discharge medium configured to output a light beam. The light source apparatus include a pair of opposed electrodes configured to excite a gas medium to form a discharge plasma. At least one electrode of the pair of opposing electrodes may include recessed portions or hollowed-out portions at each end of the electrode, or at other suitable locations. The disclosed electrode structures improve uniformity of the erosion profile of the electrodes, significantly extending the lifespan of the discharge chamber by redistributing the discharge particle flux through the electrode with an optimized design of the electrode geometry, as the local discharge particle flux is reduced at the recessed portions.

A discrete wavelength tunable laser having an optical cavity which comprises: a reflective semiconductor optical amplifier (SOA); a demultiplexer (Demux) having a single input and a plurality of outputs, the Demux configured to receive the output of the SOA and to produce a plurality of fixed spectral passbands within the gain bandwidth of the SOA; one or more tunable distributed Bragg reflector(s) (DBR(s)) arranged to receive the outputs of the Demux, each tunable DBR configured to select a reflective spectral band within the gain bandwidth of the SOA upon application of a bias current; wherein the SOA forms the back end mirror of the optical cavity; the one or more tunable DBRs form the front end mirror of the optical cavity; and wherein the lasing channel of the discrete wavelength tunable laser is chosen by the overlap of the selected reflective spectral band of one of the one or more tunable DBRs with a fixed spectral passband of the Demux.

A radiation system for controlling bursts of pulses of radiation comprises: an optical element; a controller; an actuator; and a sensor. The optical element is configured to interact with the pulses of radiation to control a characteristic of the pulses of radiation, the characteristic of the pulses of radiation being dependent on a configuration of the optical element. The controller is operable to generate a control signal. The actuator is configured to receive the control signal from the controller and to control a configuration of the optical element in dependence on the control signal. The sensor is operable to determine the characteristic of pulses having interacted with the optical element. The control signal for a given pulse in a given burst is dependent on the determined characteristic of a corresponding pulse from a previous burst.

A radiation system for controlling bursts of pulses of radiation comprises: an optical element; a controller; an actuator; and a sensor. The optical element is configured to interact with the pulses of radiation to control a characteristic of the pulses of radiation, the characteristic of the pulses of radiation being dependent on a configuration of the optical element. The controller is operable to generate a control signal. The actuator is configured to receive the control signal from the controller and to control a configuration of the optical element in dependence on the control signal. The sensor is operable to determine the characteristic of pulses having interacted with the optical element. The control signal for a given pulse in a given burst is dependent on the determined characteristic of a corresponding pulse from a previous burst.

A laser apparatus according to an aspect of the present disclosure includes a laser oscillator that outputs pulsed laser light, a deformable mirror including a deformer that deforms a reflective surface, a first processor that drives the deformer during the period for which the reflective surface reflects the pulsed laser light, a homogenizer that homogenizes the pulsed laser light reflected off the deformable mirror, and a spectrum measuring instrument that measures the spectrum of the pulsed laser light homogenized by the homogenizer.

A system includes: an optical source including a plurality of optical oscillators; a spectral analysis apparatus; and a controller. Each optical oscillator is configured to produce a light beam. The controller is configured to: determine, based on data from the spectral analysis apparatus, whether the spectral property of the light beam of one of the optical oscillators is different than the spectral property of the light beam of at least another of the plurality of optical oscillators. If the spectral property of the light beam of the first one of the optical oscillators is different than the spectral property of the light beam of another of the optical oscillators, the controller is configured to adjust the spectral property of the light beam of the first one of the optical oscillators or of the light beam of at least one other of the optical oscillators.

A line narrowing device includes a first prism; first and second gratings arranged on the optical path of the light beam having passed through the first prism at positions different in a direction of grooves of either the first grating or the second grating; a beam adjustment optical system arranged on the optical path of the light beam between the first prism and at least one grating of the first and second gratings, and causing a first portion of the light beam to be incident on the first grating and causing a second portion of the light beam to be incident on the second grating; a first actuator adjusting an incident angle of the first portion on the first grating; a second actuator adjusting an incident angle of the second portion on the second grating; and a third actuator adjusting an energy ratio of the first and second portions.

A control method of a line narrowing gas laser device includes receiving a command of either a single-wavelength mode command or a multi-wavelength mode command from an external apparatus, and controlling the line narrowing gas laser device to generate pulse laser light in accordance with the command.

A control method of a line narrowing gas laser device includes receiving a command of either a single-wavelength mode command or a multi-wavelength mode command from an external apparatus, and controlling the line narrowing gas laser device to generate pulse laser light in accordance with the command.