A laser amplifier device including an amplification element which includes a solid-state gain medium including a first main face and a second main face separated from each other by a distance which is smaller than the lateral dimensions. A heat spreader is thermally connected to, and substantially covering, the first main face. The heat spreader is optically transparent to a pump light and is in thermal contact with a heat sink. A first reflector substantially covers and faces the first main face and a second reflector substantially covers and faces the second main face; the reflectors being configured to reflect the pump light. The heat spreader and the first reflector are arranged such that the pump light passes through the heat spreader and through the first reflector and is reflected multiple times across the amplification element, between the first and second reflectors.

A laser system having a multi-pass amplifier system which includes at least one seed source configured to output at least one seed signal having a seed signal wavelength, at least one pump source configured to output at least one pump signal, at least one multi-pass amplifier system in communication with the seed source and having at least one gain media, a first mirror, and at least a second mirror therein, the gain media device positioned between the first mirror and second mirror and configured to output at least one amplifier output signal having an output wavelength range, the first mirror and second mirror may be configured to reflect the amplifier output signal within the output wavelength range, and at least one optical system may be in communication with the amplifier system and configured to receive the amplifier output signal and output an output signal within the output wavelength range.

A compact laser system with a folded annular resonator cavity defined by spherical mirrors (17, 18), enabling the generation of a multipass beam path between the mirrors, each beam pass inclined at a small angle to the axis between the mirrors to form a zig-zag path (28, 29) therebetween. A long optical path is achieved within a short physical structure. The optical resonator cavity is confined in the gap between two cylindrical coaxial electrodes (13, 14) receiving RF power to excite the lasing gas. Apertures (23) are provided in the main cavity mirrors (17, 18), with a high reflectivity end mirror (24) behind one aperture at one end and a partially reflective output coupler (25) at the other end. A channeled ceramic cylindrical element (15, 20) within the annular shaped gap between the two cylindrical electrodes confines the lasing gas to the channels (16).

A laser apparatus according to the present disclosure includes an excitation light source configured to output excitation light, a laser crystal disposed on an optical path of the excitation light, a first monitor device disposed on an optical path of transmitted excitation light after having transmitted through the laser crystal to monitor the transmitted excitation light, a temperature adjustment device configured to adjust a temperature of the excitation light source to a constant temperature based on a temperature command value, and a controller configured to change the temperature command value based on a result of monitoring by the first monitor device.

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.

An amplified laser device is provided with one or more Micro-Electro-Mechanical System (MEMS) Micro-Mirror Arrays (MMAs) having tip, tilt and piston capability positioned on either side of the optical amplifier to correct the profile of the beam to improve the gain performance of the optical amplifier or to compensate for atmospheric distortion while steering the amplified beam over a FOR. The MEMS MMAs may be positioned in front of, behind or on both sides of the amplifier. The MEMS MMAs can be configured to optimize the combined amplifier performance, static and time varying, and compensation for atmospheric distortion together or separately.

A laser pumping assembly includes a parallelepipedal solid laser medium having the shape of a plate in a horizontal plane (xy) and a thickness e.sub.L, the laser medium having an absorption spectral band and an associated absorption coefficient α; at least one light emission module intended to pump the laser medium, comprising a fluorescent parallelepipedal crystal called a concentrator, having the shape of a plate of thickness e.sub.c′, the concentrator having at least one illumination face illuminated by electroluminescent radiation and being configured to absorb the electroluminescent radiation and emit fluorescence radiation in a spectral range exhibiting an overlap with the absorption spectral band, the concentrator having an emitting face; the concentrator being in optical contact, via the emitting face, with a receiving face of the laser medium, the concentrator being arranged perpendicular to the laser medium such that the one or more illumination faces are perpendicular to the receiving face so as to perform transverse pumping of the laser medium, the optical contact being designed such that a portion of the fluorescence radiation trapped in the concentrator by total internal reflection is able to pass into the laser medium by passing through the emitting face, and be trapped in the laser medium by total internal reflection, the thickness e.sub.l of the laser medium being such that e.sub.L≤L.sub.abs/5 where L.sub.abs=1/α is an absorption length of the laser medium.

A passively Q-switched laser with intracavity pumping is described. The passively Q-switched laser has an optically pumped gain element and a saturable absorber element. The optically pumped gain element is situated in an extended cavity of a VECSEL (Vertical Extended Cavity Surface Emitting Laser) so that the gain element is pumped by a circulating pump beam of the VECSEL. The passively Q-switched laser may produce output pulses at an eye-safe wavelength using a low gain laser transition and may use a plurality of surface emitting gain regions to pump the passively Q-switched laser.

A laser system is described, the laser system comprising: an optical cavity defined by at least first and second at least partially reflecting elements; and a gain system. The gain system comprising at least first and second gain media located within the optical cavity. The first and second gain media are configured to generate optical radiation of at least first and second wavelength ranges in response to pumping energy.

A compact laser is provided for in accordance with an exemplary embodiment in the present disclosure includes a compact resonator structure using a non-planar geometry of bulk components. The laser includes a preferred rotational direction of lasing modes and employs bulk components for establishing the preferred rotational direction of lasing modes within resonator. In some embodiments, the preferred rotational direction of lasing modes is established using a reflective element that is outside the resonator structure. In some embodiments, the reflective element induces polarization shifts in the reflected light that are compensated for by a wave plate, which may be outside the resonator structure.