A laser apparatus and a polycrystalline material are described. The apparatus includes the polycrystalline material which is configured to receive pumping light at a pump wavelength and to produce an optical gain for laser oscillation at a laser wavelength different from the pump wavelength. The polycrystalline material includes a ceramic material with a predetermined grain size. The polycrystalline material further includes a rare earth dopant with a predetermined concentration, wherein the predetermined grain size and the predetermined concentration cause the polycrystalline material to exhibit the optical gain at the laser wavelength.

In one embodiment, a lidar system includes a light source configured to emit light at one or more wavelengths between 1200 nm and 1400 nm. The lidar system also includes a scanner configured to scan the emitted light across a field of regard of the lidar system and a receiver configured to detect a portion of the emitted light scattered by a target located a distance from the lidar system. The lidar system further includes a processor configured to determine the distance from the lidar system to the target based at least in part on a round-trip time for the portion of the emitted light to travel from the lidar system to the target and back to the lidar system.

Embodiments discussed herein refer to LiDAR systems and methods that enable substantially instantaneous power and frequency control over fiber lasers. The systems and methods can simultaneously control seed laser power and frequency and pump power and frequency to maintain relative constant ratios among each other to maintain a relatively constant excited state ion density of the fiber laser over time.

An optical parametric oscillator and method for generating coherent signal light involve a resonant optical cavity for coherent signal light, and in the cavity a non-parametric gain element for amplifying the coherent signal light to only partially compensate for passive optical roundtrip losses, thereby obtaining lower effective roundtrip losses. A parametric gain element is arranged in the cavity, for converting coherent pump light into coherent signal light through an instantaneous nonlinear optical interaction. The parametric oscillator has means for adjusting an intracavity optical power of the coherent pump light above a threshold value, where the parametric gain is balancing the effective roundtrip losses, thus inducing sustained oscillations of the signal light in the optical cavity. The non-parametric gain element is configured to have a limited non-parametric gain over a gain bandwidth of the parametric gain element, which is less than the passive optical roundtrip losses in the gain bandwidth.

A laser device may include a laser resonator; a chamber arranged on an optical path of the laser resonator; a pair of electrodes arranged in the chamber; a power source applying a voltage to the electrodes; a storage unit storing a voltage value; and a control unit configured to set an application voltage value of the voltage applied to the electrodes as setting the application voltage value for outputting a pulse whose pulse number is equal to or larger than 1 and smaller than i based on the voltage command value and the voltage value stored in the storage unit, and setting the application voltage for outputting a pulse whose pulse number is equal to or larger than i and smaller than j based on the voltage command value and an offset value corresponding to the voltage command value, where i>1 and j>i.

A radially polarized optical parametric amplifier insensitive to polarization is provided by the present invention, which comprises a laser module and a nonlinear crystal satisfying the type-II phase matching or the type-II quasi-phase matching condition, wherein the laser module is configured to generate two laser beams, namely the pump light and the signal light with an arbitrary polarization state, the wavelengths of the pump light and the signal light are degenerate or nearly degenerate; and the nonlinear crystal is provided in the emergent beamline of the laser module to perform optical parametric amplification of the signal light by using the pump light.

A device may determine at least one metric related to a plurality of laser pulses associated with a Q-switched laser. The device may determine a statistical metric for the at least one metric related to the plurality of laser pulses. The device may determine that the statistical metric satisfies a threshold level of deviation of the at least one metric related to the plurality of laser pulses from a baseline value for the at least one metric. The device may indicate laser degradation of the Q-switched laser based on determining that the statistical metric satisfies the threshold.

The present description relates, according to one aspect, to a high-peak-power laser pulse generation system (10), comprising at least one first light source (101) for emitting first laser pulses (I.sub.L), a fiber device (110) for transporting said first laser pulses, comprising at least one first multimode fiber with a single core designed to receive said first laser pulses, and a module (102) for temporally shaping said first laser pulses, arranged upstream of the fiber device, configured so as to reduce the power spectral density of said pulses by reducing the temporal coherence.

The present invention discloses a distributed pulsed light amplifier based on optical fiber parameter amplification, comprising a pump pulsed light source, a sensing pulsed light source, a synchronization device, a two-in-one optical coupler, an optical circulator, a parameter amplification optical fiber, a first optical filter, a photoelectric detector and a signal acquisition device. According to the distributed pulsed light amplifier, high-power pulsed light is used as pump light to generate an optical fiber parameter amplification effect near a zero-dispersion wavelength of an optical fiber, thereby amplifying a power of another sensing pulsed light. Meanwhile, due to the fact that effective optical fiber parameter amplification cannot be achieved through low-power light leakage outside a duration interval of the pump pulsed light, leaked light from the sensing pulsed light cannot be amplified, and the effect of amplifying a pulse extinction ratio can be achieved at the same time.

Provided is a laser oscillation element including a cholesteric liquid crystal layer, in which even in a case where the intensity of excitation light is weak, laser oscillation can be induced. The laser oscillation element includes a cholesteric liquid crystal layer obtained by cholesteric alignment of a liquid crystal compound, in which in a cross-section of the cholesteric liquid crystal layer observed with a scanning electron microscope, bright portions and dark portions derived from the cholesteric liquid crystalline phase are tilted with respect to a main surface of the cholesteric liquid crystal layer, the cholesteric liquid crystal layer includes a colorant that emits light by excitation, and a luminescence wavelength range of the colorant and a selective reflection wavelength range of the cholesteric liquid crystal layer at least partially overlap each other.