A method of manufacturing a semiconductor includes generating plasma in an amplifying tube using gas as a gain medium; detecting a state of the plasma generated in the amplifying tube; determining a virtual laser gain based on the detected state of the plasma; controlling the state of the plasma such that the virtual laser gain is within a target range; and manufacturing the semiconductor device including performing an exposure process on a substrate using a laser beam output from the amplifying tube adjusted to have the virtual laser gain within the target range.

Devices and methods are described herein to measure optical power in scanning laser projectors. In general, the devices and methods utilize a filter component and photodiode to measure optical power being generated by at least one laser light source, with the filter component configured to at least partially compensate for the non-uniform electric current response of the photodiode. Such a configuration facilitates accurate optical power measurement using only one photodiode, and thus can facilitate accurate optical power measurement in a relatively compact device and with relatively low cost.

The laser system may include first and second laser apparatuses and a beam delivery device. The first laser apparatus may be provided so as to emit a first laser beam to the beam delivery device in a first direction. The second laser apparatus may be provided so as to emit a second laser beam to the beam delivery device in a direction substantially parallel to the first direction. The beam delivery device may be configured to bundle the first and second laser beams and to emit the first and second laser beams from the beam delivery device to a beam delivery direction different from the first direction.

A stabilized laser source includes a fiber-ring Brillouin laser that incorporates a circulator for non-reciprocal operation and for launching of a pump optical signal. Most of the pump optical signal is launched in a forward direction and drives Brillouin laser oscillation in the backward direction, a portion of which exits via an optical coupler as the optical output of the laser source. A small fraction of the pump optical signal is launched in the backward direction via the optical coupler, and a fraction of that backward-propagating pump optical signal exits via the optical coupler as an optical feedback signal. A frequency-locking mechanism receives the optical feedback signal and controls the pump optical frequency to maintain resonant propagation of the backward-propagating pump optical signal. A second pump optical signal can be launched in the forward direction to generate a second Brillouin laser oscillation.

An optical device may include a laser emitter to generate a first laser beam and a second laser beam with orthogonal polarization states. The optical device may include first and second photodetectors to generate respective first currents based on optical powers of the first and second laser beams. The optical device may include a polarization-based beam splitter to combine the first and second laser beams. The optical device may include a wavelength filter to filter the first and second laser beams based on respective wavelengths of the first and second laser beams. The optical device may include a third photodetector and a fourth photodetector to generate respective second currents based on optical powers of the first and second laser beams after filtration. The wavelengths of the first and second laser beams may be controlled based on the first currents and the second currents.

A narrow linewidth laser in which an all-optical feedback line-up is used to improve the linewidth from a conventional laser source, such as a laser diode. The feedback line-up comprises an optical device having a controllable unbalanced optical coupler arranged on a cavity input path to couple a source signal from the laser source into the optical cavity, and to couple a seed signal received back from the optical cavity into the laser source. The seed signal has a lower power than the source signal. The unbalanced optical coupler may be an optical isolator arranged to couple the seed signal into the laser source at a power level selected to promote preferential stimulated emission within a narrower linewidth. By controlling the power of seed signal such that only a small portion thereof influences the lasing cavity, the narrowing effect of the preferential stimulated emission can be enhanced.

A device may include a first photodetector to generate a first current based on an optical power of an optical beam. The device may include a beam splitter to split a portion of the optical beam into a first beam and a second beam. The device may include a wavelength filter to filter the first beam and the second beam. The wavelength filter may filter the second beam differently than the first beam based on a difference between an optical path length of the first beam and an optical path length of the second beam through the wavelength filter. The device may include second and third photodetectors to respectively receive, after the wavelength filter, the first beam and the second beam and to generate respective second currents.

Disclosed herein is a single pulse laser apparatus that includes: a resonator having a first mirror, a second mirror, a gain medium, an electro-optic modulator (EOM) configured to perform single pulse switching, and an acousto-optic modulator (AOM) configured to perform mode-locking; a photodiode configured to measure a laser beam oscillated in the resonator; a synchronizer configured to convert an electrical signal, which is generated by measuring the laser beam, into a transistor-transistor logic (TTL) signal; a delay unit configured to set a delay time for the TTL signal to synchronize the EOM and the AOM and output a trigger TTL signal according to the delay time; an AOM driver configured to input the trigger TTL signal to the AOM that performs mode-locking and drive the AOM; and an EOM driver configured to input the trigger TTL signal to the EOM that performs single pulse switching and drive the EOM.

A calculation part calculates a maximum temperature reached which is reached by the coolant or component of each part, in the case of machining in accordance with laser machining conditions that were inputted or set, based on the cooling capacity of a chiller, tank volume of the chiller, heat generation amount from the laser oscillator, heat capacity of a cooled part of the laser device, etc. which are recorded in a recording part, and the temperature of each part measured by temperature detection parts, etc. In the case that the maximum temperature reached would exceed the allowed maximum temperature, a warning is made prior to starting laser machining.

A laser-frequency stabilizer includes: a light detector that converts a laser beam passing through an iodine cell to an optical output signal, an actuator that changes a resonator length in accordance with a received output voltage, and a control unit that controls the output voltage applied to the actuator. The control unit searches for a target saturated absorption line based on the optical output signal and, when the output voltage when the target saturated absorption line is found is within a normal voltage range that is predetermined corresponding to the target saturated absorption line, locks a oscillation frequency of the laser beam to the target saturated absorption line.