A laser medium unit 10 in a laser beam amplification device includes a plurality of laser media 14. A cooling medium flow path F1 is provided around the laser medium unit 10 to cool the laser medium unit 10 from outside. A sealed space between the laser media 14 is filled with gas or liquid, and a laser beam for passing through the sealed space is not interfered by a cooling medium flowing outside. Therefore, a fluctuation of an amplified laser beam is prevented, and a quality such as stability and focusing characteristics of the laser beam is improved.

The purpose of the present invention is to provide a laser device that makes it possible to minimize condensation in a closed space by means of a simple structure. This laser device comprises a closed space (S4) in which an optical system (31) for transmitting laser light is accommodated and a dew point adjustment flow path (5) of which at least one part is a flow path wall section formed from a transmissive material (51) through which gas molecules including water vapor are transmitted and dust and oil mist are not transmitted. The transmissive material (51) separates the interior of the dew point adjustment flow path (5) and the closed space (S4).

A laser apparatus that can generate a high-quality laser beam is provided. The laser apparatus is provided with a laser medium and an insulation layer. The laser medium has a first surface and a second surface. Incident laser light is incident on the first surface. The second surface totally reflects the incident laser light that is incident to the second surface at an incident angle equal to or larger than a critical angle. The insulation layer covers a second area of the second surface that surrounds a first area of the second surface, the first area totally reflecting the incident laser light. The laser medium is exposed in the first area.

A high-efficiency laser pumping device is provided, wherein a dielectric with or without a tapered aperture is used to accept, guide, and concentrate a pump light toward a laser gain material. Preferably, the dielectric is also a heat insulator between the pump-light source and the laser gain material. The pump-light source includes an array of light-emitting diodes, or an array of laser diodes, or an array of mixed light-emitting-diodes and laser diodes. Preferably, the input and output faces of the dielectric are optically coated with dielectric layers to maximize the pump brightness toward the laser gain material. A high-efficiency laser-pumping system with active cooling apparatus is further provided, wherein a plural number of the optical-guiding and thermal-insulation dielectrics are arranged to receive the pump lights from a plural number of pump-light sources, configured to concentrate all the pump light toward a laser gain material.

An actively cooled end-pumped solid-state laser gain device includes a bulk solid-state gain medium. An input-end of the gain medium receives a pump laser beam incident thereon and propagating in the direction toward an opposite output-end. The metal foil is disposed over a face of the gain medium extending between the input- and output-ends. A housing cooperates with the metal foil to form a coolant channel on the face the gain medium. The coolant channel has an inlet and an outlet configured to conduct a flow of coolant along the metal foil from the input-end towards the output-end. The metal foil is secured between the gain medium and portions of the housing running adjacent to the coolant channel. The metal foil provides a reliable thermal contact and imparts little or no stress on the bulk gain medium.

A laser system includes a laser diode that, upon activation, selectively produces a continuous wave of laser light or uniformly spaced, intermittent pulses of laser light. The system further includes a laser focuser with a plurality of lenses that focus the laser light produces by the laser diode and direct the laser light to an optical resonator. The optical resonator includes a lasing medium that, when intersected by the laser light from the laser diode, produces a beam of laser light with a wavelength that may be used for therapeutic treatment. The system is operable to produce the therapeutic laser light when the laser diode is operating in either the continuous wave mode or the pulsed mode, without moving components of the system relative to one another.

Laser amplifier apparatus 100 includes gain medium 10 for receiving seed pulse(s) 2 and pump pulse(s) 3 and for emitting laser pulse(s) 1, resonator device 20 including gain medium and resonator mirrors spanning resonator beam path 25 with multi-pass geometry, coupler arrangement 30 for coupling seed pulse(s) and pump pulse(s) to resonator device and coupling output laser pulse(s) out of resonator device, and gain medium cooling device 40A. Resonator mirrors include first and second telescope mirrors 21, 22 with mutual distance and common focal section therebetween and defining optical axis z of resonator device, and first and second groups of end mirrors 23, 24 between mirrors 21 and 22 for forming path 25, wherein end mirrors are on ring-shaped section surrounding optical axis z, and resonator are arranged such that emitting sections of the gain medium are imaged in themselves. A method of amplifying laser pulses is also described.

The present disclosure provides a method for aligning a master oscillator power amplifier (MOPA) system. The method includes ramping up a pumping power input into a laser amplifier chain of the MOPA system until the pumping power input reaches an operational pumping power input level; adjusting a seed laser power output of a seed laser of the MOPA system until the seed laser power output is at a first level below an operational seed laser power output level; and performing a first optical alignment process to the MOPA system while the pumping power input is at the operational pumping power input level, the seed laser power output is at the first level, and the MOPA system reaches a steady operational thermal state.

It is an aim of the present invention to provide ultra-compact highly-integrated diffraction-grating semiconductor lasers on chips. Various embodiments combined enable the lasers to be compact in size, light weight, mechanically rugged, low in manufacturing cost, and in some cases high in electrical wall-plugged power efficiency or high in optical power output, comparing to typical lasers based on discrete optical components.

A heat sink assembly may include an alignment body with an opening configured to receive a crystal rod, wherein the opening is configured to maintain a crystalline orientation of the crystal rod relative to a physical orientation of the alignment body. The heat sink assembly may include a first cooling stack, wherein the first cooling stack includes a first cutout to receive the crystal rod and the alignment body. The heat sink assembly may include a second cooling stack, wherein the second cooling stack includes a second cutout to receive the crystal rod and the alignment body, and wherein the first cooling stack and the second cooling stack are configured to mate and at least partially sandwich the crystal rod and the alignment body.