A light source apparatus (200) includes a gas discharge stage (210) and a metal fluoride trap (300). The gas discharge stage includes an optical amplifier (206) and a set of optical elements (250, 260). The optical amplifier includes a chamber (211) configured to hold a gas discharge medium (213), the gas discharge medium outputting a light beam. The set of optical elements is configured to form an optical resonator around the optical amplifier. The metal fluoride trap is configured to trap metal fluoride dust generated from the gas discharge stage. The metal fluoride trap includes an electrostatic precipitator (320) and a packed-bed filter (400, 402, 404) disposed around the electrostatic precipitator. The packed-bed filter includes a plurality of beads configured (406, 408) to absorb metal fluoride dust (208).

An optical system for increasing contrast of pulsed laser radiation includes a first polarization setting optical unit for setting an elliptical polarization state of the pulsed laser radiation, and a multipass cell having at least two opposing mirrors. The pulsed laser radiation passes the multipass cell with formation of a plurality of intermediate focus zones. The multipass cell is filled with a gas having an optical nonlinearity that causes an intensity-dependent rotation of an alignment of the elliptical polarization state of the pulsed laser radiation, such that the multipass cell outputs beam portions having differently aligned elliptical polarization states on account of the intensity-dependent rotation. The optical system further includes an optical beam splitting system for splitting the beam portions having differently aligned elliptical polarization states.

A system and method for automatically performing gas optimization after a refill in the chambers of a two chamber gas discharge laser is disclosed. The laser is fired at low power, and the gas in the amplifier laser chamber bled if necessary until the discharge voltage meets or exceeds a minimum value without dropping the pressure below a minimum value. The power output is increased to a burst pattern that approximates the expected operation of the laser, and the amplifier chamber gas bled again if necessary until the voltage and an output energy meet or exceed minimum values, or until the pressure is less than a minimum value. The gas in the master oscillator chamber is then bled if necessary until the output energy of the master oscillator meets or falls below a maximum value, again without dropping the pressure in the chamber below the minimum value. While the pressure is adjusted, bandwidth is also measured and adjusted to stay within a desired range. Once the target values are provided, the process runs quickly without manual interaction.

Disclosed are methods and apparatus for generating a sub-200 nm continuous wave (cw) laser. A laser apparatus includes a chamber for receiving at least a rare gas or rare gas mixtures and a pump laser source for generating at least one cw pump laser focused in the chamber for generating at least one laser-sustained plasma in the chamber. The laser apparatus further includes a system for forming an optical cavity in which the at least one laser-sustained plasma serves as an excitation source for producing at least one cw laser having a wavelength that is below about 200 nm. In one aspect, the at least one laser-sustained plasma has a shape that substantially matches a shape of the optical cavity.

A gas laser, including: a semiconductor laser, an optical beam-shaping system, a pair of electrodes, a discharge tube, a rear mirror, and an output mirror. The pair of electrodes includes two electrodes. The electrodes are symmetrically disposed at an outer layer of the discharge tube in parallel. The electrodes are connected to a radio-frequency power supply via a matching network, and the electrodes operate to modify working gas in the discharge tube through radio-frequency discharge. The rear mirror and the output mirror are disposed at two end surfaces of the discharge tube, respectively. The rear mirror, taken together with the output mirror and the discharge tube, form a resonant cavity. The output mirror is configured to output a laser beam.

An optical compensation system for a laser beam and an excimer laser annealing device are provided in the present disclosure. The optical compensation system for the laser beam includes a laser source, a beam splitter and a reversion assembly. The laser beam emitted by the laser source enters the beam splitter, and is divided by the beam splitter into a first light beam and a second light beam having different transmission paths. The second light beam is reversed and reflected by the reversion assembly, enters the beam splitter, and exits from the beam splitter together with the first light beam. An asymmetry of the second light beam reversed by the reversion assembly is different from an asymmetry of the first light beam.

A laser system includes a laser radiation source for providing pulsed laser radiation, and an optical system that includes a first polarization setting optical unit configured to set a circular polarization state of the pulsed laser radiation and a multipass cell having at least two mirrors. The pulsed laser radiation passes through the multipass cell with formation of a plurality of intermediate focus zones. The multipass cell is filled with a filling gas that has an optical nonlinearity and causes a spectral broadening of the pulsed laser radiation in the intermediate focus zones. A pressure of the filling gas is set in a pressure range so that there is an ionization behavior of the filling gas in a form of multiphoton ionization. Focus diameters of the intermediate focus zones are set such that the pulsed laser radiation passes through the multipass cell without ionization of the filling gas.

The present invention provides a laser, including: a medium, having a ground state, an intermediate state, and an excited state in ascending order of energy; an excitation system, configured to excite electrons in the medium from the ground state to the intermediate state; and an excitation laser, configured to drive electrons in the intermediate state at different spatial positions in the medium to the ground state through a stimulated emission process with a fixed phase relationship, to generate a laser with a shorter relative wavelength. Due to the use of an excitation laser to drive electrons from the intermediate state, the photons generated by the stimulated emission have coherence, thereby forming a laser. In the present invention, an excitation system performing primary pumping combined with an excitation laser with a relatively long wavelength performing secondary pumping generate lasers with a relatively short wavelength, and the structure of the short-wavelength laser is simple, compact, and easy to be implemented. In addition, the cost of the short-wavelength laser can be reduced, and a laser with a shorter wavelength can be obtained.

An optical compensation system for a laser beam and an excimer laser annealing device are provided in the present disclosure. The optical compensation system for the laser beam includes a laser source, a beam splitter and a reversion assembly. The laser beam emitted by the laser source enters the beam splitter, and is divided by the beam splitter into a first light beam and a second light beam having different transmission paths. The second light beam is reversed and reflected by the reversion assembly, enters the beam splitter, and exits from the beam splitter together with the first light beam. An asymmetry of the second light beam reversed by the reversion assembly is different from an asymmetry of the first light beam.

A light source apparatus includes an airtight container having a hemispherical or semielliptical first curved portion configured to receive laser light, a hemispherical or semielliptical second curved portion opposite to the first curved portion, and a cylindrical portion connecting the first curved portion and the second curved portion; assist gas sealed in the airtight container; and a light source configured to irradiate laser light to the first curved portion from outside of the airtight container.