A laser apparatus according to the present disclosure includes: a laser output unit configured to perform laser oscillation; and a control unit configured to acquire first laser performance data obtained when the laser output unit performs laser oscillation based on a first laser control parameter, and second laser performance data obtained when the laser output unit performs laser oscillation based on a second laser control parameter, while laser output from the laser output unit to an external device is stopped, and determine whether the second laser performance data has been improved as compared to the first laser performance data.

A method includes driving, while producing a burst of pulses at a pulse repetition rate, a spectral feature adjuster among a set of discrete states at a frequency correlated with the pulse repetition rate; and in between the production of the bursts of pulses (while no pulses are being produced), driving the spectral feature adjuster according to a driving signal defined by a set of parameters. Each discrete state corresponds to a discrete value of a spectral feature. The method includes ensuring that the spectral feature adjuster is in one of the discrete states that corresponds to a discrete value of the spectral feature of the amplified light beam when a pulse in the next burst is produced by adjusting one or more of: an instruction to the lithography exposure apparatus, the driving signal to the spectral feature adjuster, and/or the instruction to the optical source.

It is an aim of the present invention to provide ultra-compact highly-integrated diffraction-grating semiconductor lasers on chips. Various embodiments combined enable the lasers to be compact in size, light weight, mechanically rugged, low in manufacturing cost, and in some cases high in electrical wall-plugged power efficiency or high in optical power output, comparing to typical lasers based on discrete optical components.

Provided is a fixing device for a diffraction element including an element installation portion where a diffraction element is installed, and an element fixing portion that fixes the diffraction element installed on the element installation portion, wherein the element installation portion includes an element installation surface for curving the installed diffraction element in a discretionary shape, and the element installation surface is formed in an arch-like shape such that deformation of the diffraction element due to pressure of a cooling fluid is reduced.

A pulse width expansion apparatus according to an aspect of the present disclosure includes a polarization beam splitter and a transfer optical system. The transfer optical system includes ¼-wavelength and reflection mirror pairs. The ¼-wavelength mirror pair include first and second ¼-wavelength mirrors. The first ¼-wavelength mirror provides ¼-wavelength phase shift and reflects a pulse laser beam. The second ¼-wavelength mirror provides ¼-wavelength phase shift and reflects the pulse laser beam reflected by the first ¼-wavelength mirror. The reflection mirror pair are disposed on an optical path before and after or between the ¼-wavelength mirror pair. The transfer optical system transfers an image of an input pulse laser beam on the polarization beam splitter to the optical path between the ¼-wavelength mirror pair at one-to-one magnification as a first transfer image and transfers the first transfer image to the polarization beam splitter at one-to-one magnification as a second transfer image.

An information processing device includes a processor and a storage device. The processor is configured to acquire data for each parameter provided from each of a light source device which generates pulse light and an exposure apparatus which performs exposure on a wafer with the pulse light output from the light source device, and time data associated with the data; to perform classification, based on the acquired data and time data, for each record of the data associated with same time data for distinguishing whether being data during exposure in which the wafer is irradiated with the pulse light or being data during non-exposure; to associate attribute information indicating an attribute according to the classification with each of the records; to cause the storage device to store the data and the time data associated with the attribute information; and to generate a chart using data read from the storage device.

A laser beam delivery system includes an optical beam launcher device and a waveguide assembly. The optical beam launcher device includes an optical relay system that includes a beam splitting optic that is configured to cause a laser beam that is input into the optical beam launcher device to be split into a first laser sub-beam and a second laser sub-beam, cause the first laser sub-beam to transmit to a first region of an input lens of the waveguide assembly, and cause the second laser sub-beam to transmit to a second region of the input lens. The waveguide assembly is configured to transmit the first laser sub-beam and the second laser sub-beam from the input lens to an output lens of the waveguide assembly, wherein the first laser sub-beam and the second laser sub-beam transmit from the waveguide assembly and form an output laser beam.

A single-frequency laser apparatus comprises a mirror and a volume Bragg grating (VBG) reflector defining a laser cavity therebetween and an optical gain material for emitting and amplifying an intra-cavity beam in the laser cavity. The optical gain material comprises a transition-metal doped crystal such as a crystal doped with transition-metal ions selected from one or more of Ti.sup.3+ ions, Cr.sup.2+ ions, Cr.sup.3+ ions or Cr.sup.4+ ions. A reflectivity spectrum of the VBG reflector and an optical length of the laser cavity are selected so that a beam output from the laser cavity is a single-frequency output beam and/or includes only one longitudinal mode of the laser cavity. The laser apparatus may provide a robust, compact, low cost, high-power wavelength adjustable (from approximately 650 to 950 nm), narrow linewidth (<100 kHz), single frequency laser source which is suitable for a wide range of applications from laser sensing, spectroscopy, and high precision frequency metrology sectors.

A spectral feature selection apparatus includes a dispersive optical element arranged to interact with a pulsed light beam; three or more refractive optical elements arranged in a path of the pulsed light beam between the dispersive optical element and a pulsed optical source; and one or more actuation systems, each actuation system associated with a refractive optical element and configured to rotate the associated refractive optical element to thereby adjust a spectral feature of the pulsed light beam. At least one of the actuation systems is a rapid actuation system that includes a rapid actuator configured to rotate its associated refractive optical element about a rotation axis. The rapid actuator includes a rotary stepper motor having a rotation shaft that rotates about a shaft axis that is parallel with the rotation axis of the associated refractive optical element.

An optically pumped on-chip solid-state laser includes a solid gain media substrate and a laser generating structure disposed above the solid gain media substrate. The laser generating structure includes a resonator, a pump light input structure, and a laser light output structure; and the resonator is disposed between the pump light input structure and the laser light output structure, and is propped against or is in clearance fit with the solid gain media substrate.