A laser device includes a laser configured to generate laser light and a laser control module configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, wherein the laser control module includes a tunable frequency discriminating element which is preferably continuously frequency tunable, and where the laser control module is placed outside the laser cavity.

A laser (14) includes an optical amplifier array system (17) that generates a plurality of laser beams (24); and a beam combiner (18) that coherently combines the plurality of laser beams (24) to form a combination beam (26) having a hollow center in a near field. The combination beam (26) with the hollow center allows for the use of a beam director (19) having an on-axis, reflective beam expander (21) without (i) loss in power, (ii) degradation of beam quality, or (iii) excessive heating of the beam expander (21).

A method for providing spectral beam combining (SBC) including generating a plurality seed beams each having a central wavelength and a low fill factor profile, where the wavelength of all of the seed beams is different; amplifying the seed beams; causing the amplified beams to expand as they propagate so as to be converted from the low fill factor profile to a high fill factor profile where the high fill factor profile tapers to a lower value at a perimeter of each beam; causing a wavefront of the converted beams to flatten to provide a plurality of adjacent SBC beams having different wavelengths with minimal overlap and a minimal gap between the beams; collimating the SBC beams; and directing the collimated SBC beams onto an SBC element that spatially diffracts the individual beam wavelengths and directing the beams in the same direction as a combined output beam.

An optical source for a photolithography tool includes a source configured to emit a first beam of light and a second beam of light, the first beam of light having a first wavelength, and the second beam of light having a second wavelength, the first and second wavelengths being different; an amplifier configured to amplify the first beam of light and the second beam of light to produce, respectively, a first amplified light beam and a second amplified light beam; and an optical isolator between the source and the amplifier, the optical isolator including: a plurality of dichroic optical elements, and an optical modulator between two of the dichroic optical elements.

A spatially and spectrally distributed long-laser system. Spatially separated phase-conjugate mirrors (PCMs) define a long-laser resonator cavity. The PCMs define, respectively, a power transmitting unit (master), and a power receiving unit (slave), as well as providing a secure two-way communications link between the units. The long-laser is mode-locked, minimizing third-party interception and detection. A wavefront-reversal device, using a MEMS spatial phase modulator, integrated with a retroreflector array, provides a true phase-conjugate (time-reversed) replica of the beam at each end of the system, providing auto-alignment, diffraction-limited performance, compensation for static and dynamic phase and polarization distortions, minimizing the FOV and scattering. The retroreflecting array initiates the oscillation mode. The SPM adaptive optical system bootstraps the retro-array by forming a simultaneous closed-loop system. The PCM emulates a deformable mirror with an integrated cat's eye retro-array, on a pixel-by-pixel basis, equivalent to a true wave-front reversal device at each end of the system.

An optical coupler includes: input-type optical fibers; an output-type optical fiber; and radiant light processing units. The input-type optical fibers are bundled at leading end side to form a fiber bundle portion, and leading end portion of the fiber bundle portion is connected to the output-type optical fiber. In at least either the input-type optical fibers or the output-type optical fiber, a tapered portion is formed in which cross-sectional area is tapered to become narrower in light traveling direction indicating direction from the input-type optical fibers toward the output-type optical fiber. The number of the tapered portion is equal to or greater than two. Each radiant light processing unit is disposed to mutually overlap with one of the tapered portions or away from one of the tapered portions in the light traveling direction, and is disposed on outer periphery of the input-type optical fibers or the output-type optical fiber.

A laser apparatus according to an aspect of the present disclosure includes: a master oscillator; at least one amplifier disposed on an optical path of a first pulse laser beam output from the master oscillator; a sensor disposed on an optical path of a second pulse laser beam output from the at least one amplifier; and a laser controller. The laser controller causes the laser apparatus to perform burst oscillation based on a burst signal from an external device, and performs processing of controlling a beam parameter based on a sensor output signal obtained from the sensor in a burst duration, and processing of detecting self-oscillation light from the amplifier based on a sensor output signal obtained from the sensor in a burst stop duration.

A laser apparatus according to an aspect of the present disclosure includes: a master oscillator; at least one amplifier disposed on an optical path of a first pulse laser beam output from the master oscillator; a sensor disposed on an optical path of a second pulse laser beam output from the at least one amplifier; and a laser controller. The laser controller causes the laser apparatus to perform burst oscillation based on a burst signal from an external device, and performs processing of controlling a beam parameter based on a sensor output signal obtained from the sensor in a burst duration, and processing of detecting self-oscillation light from the amplifier based on a sensor output signal obtained from the sensor in a burst stop duration.

Various embodiments of a multi-laser system are disclosed. In some embodiments, the multi-laser system includes a plurality of lasers, a plurality of laser beams, a beam positioning system, a thermally stable enclosure, and a temperature controller. The thermally stable enclosure is substantially made of a material with high thermal conductivity such as at least 5 W/(m K). The thermally stable enclosure can help maintain alignment of the laser beams to a target object over a range of ambient temperatures. Various embodiments of an optical system for directing light for optical measurements such laser-induced fluorescence and spectroscopic analysis are disclosed. In some embodiments, the optical system includes a thermally conductive housing and a thermoelectric controller, a plurality of optical fibers, and one or more optical elements to direct light emitted by the optical fibers to illuminate a flow cell. The housing is configured to attach to a flow cell.

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.