The present disclosure relates to an apparatus for modifying a curvature of a thin plate optic using controlled heat and densification of portions of the optic. In one embodiment the system has a support structure for supporting the optic about a perimeter thereof, a laser configured to generate a beam having a predetermined energy, and the beam being directed at one surface of the optic. The beam heats and densifies portions of the optic to create a force on the optic. The force induces a stress produces a controlled deformation of the optic. The controlled deformation at least one of modifies a curvature of, or corrects a defect in, the optic.

A laser apparatus includes a laser oscillator; an acousto-optic modulation unit including a first acousto-optic modulator that diffracts a laser beam from the laser oscillator when a first ultrasonic wave is applied and a second acousto-optic modulator that diffracts a higher order beam output from the first acousto-optic modulator when a second ultrasonic wave is applied; and an amplifier that amplifies the laser beam from the acousto-optic modulation unit, a propagation direction of the first ultrasonic wave relative to a diffracted direction of the higher order beam emitted from the first acousto-optic modulator and a propagation direction of the second ultrasonic wave relative to a diffracted direction of a higher order beam emitted from the second acousto-optic modulator being different.

A carbon dioxide gas-discharge slab-laser is assembled in a laser-housing. The laser-housing is formed from a hollow extrusion. An interior surface of the extrusion provides a ground electrode of the laser. Another live electrode is located within the extrusion, electrically insulated from and parallel to the ground electrode, forming a discharge-gap of the slab-laser. The electrodes are spaced apart by parallel ceramic strips. Neither the extrusion, nor the live electrode, include fluid coolant channels. The laser-housing is cooled by fluid-cooled plates attached to the outside thereof.

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 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.

An extreme ultraviolet light generation system may include a chamber, a first partition wall having at least one opening which provides communication between a first space and a second space, an EUV light concentrating mirror located in the second space and configured to concentrate extreme ultraviolet light generated in a plasma generation region located in the first space, a first gas supply port formed at the chamber, and a gas exhaust port formed in the first partition wall, a distance between the center of the plasma generation region and an edge of the at least one opening being equal to or more than a stop distance L.sub.STOP [mm] calculated by the following equation.

L.sub.STOP=272.8.Math.E.sub.VG.sup.0.4522.Math.P.sup.−1

E.sub.AVG [eV] representing average kinetic energy of ions generated in the plasma generation region and P [Pa] representing a gas pressure inside the first partition wall

A hair coloring appliance includes a handle and a hair color delivery system supported within the handle. A nozzle assembly is adapted to receive hair color. The nozzle assembly includes a stationary frame and a nozzle array through which the hair color is delivered to the hair and a plurality of filaments adjacent the nozzles which are longer than the nozzles, acting as a stand-off between the nozzles and the scalp. A motor reciprocates the nozzle array back and forth as hair color moves through the nozzles.

An external optical feedback element (108) for tuning an output beam of a gas laser (102) having multiple wavelengths includes a partially reflective optical element (108) positioned on a beam path of the output beam (106) outside of an internal optical cavity of the gas laser (102), and a stage (114) to support the optical element and adjust rotation, horizontal tilt angle, and vertical tilt angle of the optical element with respect to the beam path. The output beam (106) is partially reflected at the optical element (108) and fed back into the internal optical cavity of the gas laser (102), with the intensity varying for multiple wavelengths and adjusted by changing rotation, horizontal tilt angle and vertical tilt angle of the optical element. Thereby, a variable feedback of the output beam into the internal optical cavity of the gas laser is provided, which leads to a selective output wavelength of the gas laser, either at a single line or at multiple lines simultaneously. This setup may allow to control the wavelength of a commercial CO2 gas laser without a modification of the laser itself by adding a coupled cavity with a wavelength selective element like a grating to the given gas laser resonator.

A method for adjusting a laser beam includes, following passage of the laser beam through a beam-shaping device, measuring, via a detector of a detector device, a beam profile of the laser beam. The method further includes determining a beam quality property of the laser beam based on the measured beam profile and altering an adjustable optical unit for modifying at least one property of the laser beam prior to the entry into the beam-shaping device. For adjusting the laser beam, the adjustable optical unit is altered based on the determined beam quality property.

A laser system according to the present disclosure includes: a laser apparatus configured to emit a laser beam; a transmission optical system disposed on a path between the laser apparatus and a target supplied into an EUV chamber in which EUV light is generated; a reflection optical system configured to reflect, toward the target, the laser beam from the transmission optical system; a first sensor configured to detect the laser beam traveling from the laser apparatus toward the reflection optical system; a second sensor configured to detect return light of the laser beam reflected by the reflection optical system and traveling backward to the laser apparatus; and a control unit configured to determine that the reflection optical system is damaged when no anomaly of the laser beam is detected and a light amount of the return light exceeds a predetermined light amount value.