A fractional handpiece and systems thereof for skin treatment include a passively Q-switched laser assembly operatively connected to a pump laser source to receive a pump laser beam having a first wavelength and a beam splitting assembly operable to split a solid beam emitted by the passively Q-switched laser assembly and form an array of micro-beams across a segment of skin. The passively Q-switched laser assembly generates a high power sub-nanosecond pulsed laser beam having a second wavelength.

A fractional handpiece and systems thereof for skin treatment include a passively Q-switched laser assembly operatively connected to a pump laser source to receive a pump laser beam having a first wavelength and a beam splitting assembly operable to split a solid beam emitted by the passively Q-switched laser assembly and form an array of micro-beams across a segment of skin. The passively Q-switched laser assembly generates a high power sub-nanosecond pulsed laser beam having a second wavelength.

Laser annealing apparatus includes a plurality of frequency-tripled solid-state lasers, each delivering an output beam of radiation at a wavelength between 340 nm and 360 nm. Each output beam has a beam-quality factor (M.sup.2) greater of than 50 in one transverse axis and greater than 20 in another transverse axis. The output beams are combined and formed into a line-beam that is projected on a substrate being annealed. Each output beam contributes to the length of the line-beam.

Laser annealing apparatus includes a plurality of frequency-tripled solid-state lasers, each delivering an output beam of radiation at a wavelength between 340 nm and 360 nm. Each output beam has a beam-quality factor (M.sup.2) greater of than 50 in one transverse axis and greater than 20 in another transverse axis. The output beams are combined and formed into a line-beam that is projected on a substrate being annealed. Each output beam contributes to the length of the line-beam.

A laser apparatus includes at least one electro-optic (EO) medium through which a polarized laser beam passes for N times, forming a plurality of first-pass to Nth-pass beams, by reflecting the polarized laser beam from at least one reflection mirror, and a power supplier configured to alternately provide a 1/N of a half-wave (λ/2) or quarter-wave (λ/4) voltage and remove the voltage to the EO medium, λ being a wavelength of the polarized laser beam. The at least one EO medium is tilted at angle θ and/or angle di with respect to one of the plurality of first-pass to Nth-pass beams. The at least one EO medium comprises a M number of EO mediums, and the power supplier is configured to alternately provide a 1/M*N of a half-wave (λ/2) or quarter-wave (λ/4) voltage and remove the voltage to each of the M number of EO mediums.

A laser apparatus includes at least one electro-optic (EO) medium through which a polarized laser beam passes for N times, forming a plurality of first-pass to Nth-pass beams, by reflecting the polarized laser beam from at least one reflection mirror, and a power supplier configured to alternately provide a 1/N of a half-wave (λ/2) or quarter-wave (λ/4) voltage and remove the voltage to the EO medium, λ being a wavelength of the polarized laser beam. The at least one EO medium is tilted at angle θ and/or angle di with respect to one of the plurality of first-pass to Nth-pass beams. The at least one EO medium comprises a M number of EO mediums, and the power supplier is configured to alternately provide a 1/M*N of a half-wave (λ/2) or quarter-wave (λ/4) voltage and remove the voltage to each of the M number of EO mediums.

[Object] To provide a compact and high-performance laser device and a laser apparatus.

[Solving Means] A laser device according to the present disclosure includes an excitation light source having a first reflective layer with respect to a first wavelength; a laser medium having a second reflective layer with respect to a second wavelength on a first surface facing to the excitation light source and a third reflective layer with respect to the first wavelength on a second surface opposite to the first surface; and a saturable absorber having a fourth reflective layer with respect to the second wavelength on a third surface opposite to the laser medium.

[Object] To provide a compact and high-performance laser device and a laser apparatus.

[Solving Means] A laser device according to the present disclosure includes an excitation light source having a first reflective layer with respect to a first wavelength; a laser medium having a second reflective layer with respect to a second wavelength on a first surface facing to the excitation light source and a third reflective layer with respect to the first wavelength on a second surface opposite to the first surface; and a saturable absorber having a fourth reflective layer with respect to the second wavelength on a third surface opposite to the laser medium.

A system for generating extreme ultraviolet light, in which a target material inside a chamber is irradiated with a laser beam to be turned into plasma, includes a first laser apparatus configured to output a first laser beam, a second laser apparatus configured to output a pedestal and a second laser beam, and a controller connected to the first and second laser apparatuses and configured to cause the first laser beam to be outputted first, the pedestal to be outputted after the first laser beam, and the second laser beam having higher energy than the pedestal to be outputted after the pedestal.

Described herein are methods for developing and maintaining pulses that are produced from compact resonant cavities using one or more Q-switches and maintaining the output parameters of these pulses created during repetitive pulsed operation. The deterministic control of the evolution of a Q-switched laser pulse is complicated due to dynamic laser cavity feedback effects and unpredictable environmental inputs. Laser pulse shape control in a compact laser cavity (e.g., length/speed of light <˜1 ns) is especially difficult because closed loop control becomes impossible due to causality. Because various issues cause laser output of these compact resonator cavities to drift over time, described herein are further methods for automatically maintaining those output parameters.