A sub-nanosecond laser system is disclosed. The sub-nanosecond laser system may include: a pump laser source operable to generate a pump laser beam having a pump wavelength; a first pump beam splitter operable to receive the pump laser beam and split the pump laser beam into at least a first split pump laser beam and a second split pump laser beam; a passively Q-switched seed laser operable to receive the first split pump laser beam and generate a seed laser beam; and an amplifier assembly operable to receive the second split pump laser beam and the seed laser beam. The amplifier assembly may include one or more amplifiers arranged in series in a multi-stage configuration, arranged in a multi-pass configuration, or a combination thereof.

The present disclosure provides a dark cavity laser, including: a frequency stabilized laser output device configured to generate a laser light, and perform a frequency stabilized processing on the generated laser light to output it to the dark cavity laser device as a pump light of a gain medium of a dark cavity; and a dark cavity laser device including a main cavity, and a cavity of the main cavity is provided inside with a gas chamber of a gain medium of a dark cavity laser light, where the gain medium of the dark cavity laser light is alkali metal atoms; the dark cavity laser device is configured to receive the pump light, and form a polyatomic coherent stimulated radiation between transition levels of the alkali metal atoms in the gas chamber by a weak feedback of the main cavity to generate the dark cavity laser light.

The disclosure provides a high-frequency-reproducibility laser frequency stabilization method and device based on multi-point acquisition of laser tube temperature. The laser frequency stabilization device includes: a frequency stabilization control circuit. The frequency stabilization control circuit includes a polarizing beam splitter, an optical power conversion circuit, an A/D conversion circuit, a temperature measuring circuit, a microprocessor, a D/A converter and a heating film driver. The polarizing beam splitter is disposed outside any one of laser transmitting holes. The optical power conversion circuit is disposed on reflection and refraction optical paths of the polarizing beam splitter. The optical power conversion circuit, the A/D conversion circuit, the microprocessor, the D/A converter, the heating film driver and a plurality of groups of heating films are sequentially in one-way connection. Temperature sensors, the temperature measuring circuit and the microprocessor are sequentially in one-way connection. The method of the disclosure can increase the frequency reproducibility of a laser device from 10.sup.−8 to 10.sup.−9. The device of the disclosure can effectively avoid the drift of a final frequency stabilization temperature point.

In an ultrastable laser, using a large mode-volume optical resonator, which suppresses the resonator's fast thermal fluctuations, together with the stimulated Brillouin scattering (SBS) optical nonlinearity presents a powerful combination that enables the ability to lase with an ultra-narrow linewidth of 20 Hz. The laser's long-term temperature drift is compensated by using the narrow Brillouin line to sense minute changes in the resonator's temperature (e.g., changes of 85 nK). The precision of this temperature measurement enables the stabilization of resonators against environmental perturbations.

An optical amplifier which can suppress, without measuring signal beam power at individual wavelengths, wavelength-dependence of gain with respect to a signal beam into which multiple signal beams having respective wavelengths different from each other are multiplexed. The optical amplifier can suppress wavelength-dependence of gain by giving loss in accordance with a linear-loss slope to an amplified signal beam. The optical amplifier includes a variable tilt equalizer for varying a loss slope value representing the slope of the loss slope and a tilt control unit for controlling a loss slope value of the variable tilt equalizer.

A laser oscillation device includes a laser oscillation unit, which is a laser oscillation part that generates multiple first laser beams having different wavelengths from one another, multiple sensors having different sensitivity characteristics from one another each representing light-receiving sensitivity for the wavelengths of the multiple first laser beams, to each output first voltages dependent on outputs of the multiple first laser beams. The laser oscillation device includes a computing unit that corrects the multiple first voltages using the sensitivity characteristics of the multiple sensors, and controls the laser oscillation unit based on multiple second voltages which correspond to multiple first voltages obtained after the correction.

A laser oscillation device includes a laser oscillation unit, which is a laser oscillation part that generates multiple first laser beams having different wavelengths from one another, multiple sensors having different sensitivity characteristics from one another each representing light-receiving sensitivity for the wavelengths of the multiple first laser beams, to each output first voltages dependent on outputs of the multiple first laser beams. The laser oscillation device includes a computing unit that corrects the multiple first voltages using the sensitivity characteristics of the multiple sensors, and controls the laser oscillation unit based on multiple second voltages which correspond to multiple first voltages obtained after the correction.

An all solid-state laser light source device comprises a diode-pump laser and the following devices sequentially arranged in an optical path direction of laser light: a coupling optical fiber, a coupling lens assembly, and a resonant cavity. An anisotropic laser crystal is provided in the resonant cavity. Absorption spectra of the anisotropic laser crystal comprise a π polarization absorption spectrum and a σ polarization absorption spectrum. Each of the π polarization absorption spectrum and the σ polarization absorption spectrum has a peak pump region and a left pump region and a right pump region arranged on either side of the peak pump region. Pump light outputted by diode-pump laser has a wavelength λ falling within the left pump region or the right pump region.

A laser system has a fiber cable, a pump enclosure connected to the fiber cable outside of the pump enclosure, and a laser-head enclosure connected to the fiber cable disposed outside of the laser-head enclosure. The pump enclosure houses a fiber-coupled laser diode configured to produce and convey pump light through the pump enclosure out to the fiber cable. The laser-head enclosure houses a crystal. The pump light, when produced by the laser diode, propagates out from the pump enclosure through the fiber cable into the laser-head enclosure and into the crystal. The crystal produces a laser beam in response to the pump light. The integrated fiber of the laser diode, the fiber cable, and internal fiber of the laser-head enclosure, through which the pump light propagates, may be single-mode fibers, to achieve superior laser system performance with lower frequency and intensity noise than pumping through multimode fibers.

A laser apparatus calculates a temperature of a temperature increase portion that is raised in temperature by reflection light, and determines and outputs an emergency optical output command with the aim of ensuring that the calculated temperature does not exceed a first predetermined temperature, which is set at a lower temperature than an upper limit heat resistance temperature, and if necessary, controlling the temperature to or below a second predetermined temperature set at a lower temperature than the first predetermined temperature. When the emergency optical output command is to be output, a control unit switches an optical output command output thereby to the emergency optical output command and outputs the emergency optical output command.