A laser beam combining device with an unstable resonator cavity includes a semiconductor laser source configured to emit a plurality of laser beams to a beam shaper to form a plurality of parallel laser beams and the parallel laser beams are focused, by a transform lens, to a diffraction grating, wherein the diffraction grating diffracts the focused laser beams to form a combined laser beam, wherein the transform lens is disposed between the semiconductor laser source and the diffraction grating and an output coupler including a cylindrical surface with partial reflection coating, wherein a portion of the combined laser beams is oscillated between the cylindrical surface and the back facet of the semiconductor laser, and the portion of the combined laser beams is emitted via the output coupler.

A wavelength combining laser apparatus includes: a semiconductor laser emitting laser beams in an optical-axial direction perpendicular to a laser beam combining direction; a wavelength combining element combining the laser beams in the laser beam combining direction into a single laser beam; a cross-coupling reduction optical system having positive power in the laser beam combining direction perpendicular to an optical axis of the single laser beam output from the wavelength combining element; and a partially-reflective mirror reflecting the single laser beam having passed through the cross-coupling reduction optical system and also allowing the single laser beam to transmit through and exit the partially-reflective mirror. The cross-coupling reduction optical system is disposed to image the light emitting end face on the partially-reflective mirror by causing the light emitting end face to be conjugate to the partially-reflective mirror in a plane formed by the optical axis and the laser beam combining direction.

A semiconductor light emitting device includes: a semiconductor light emitting element including a substrate and a plurality of light emitters arranged along an upper surface of the substrate; a first base disposed below a lower surface of the substrate; and a first bonding layer which bonds the semiconductor light emitting element to the first base. In the semiconductor light emitting device, a thermal conductivity of the substrate is higher than a thermal conductivity of the first bonding layer, and a thickness of the first bonding layer is less on one end side than on an other end side in an arrangement direction in which the plurality of light emitters are arranged.

In various embodiments, laser devices include a thermal bonding layer featuring an array of carbon nanotubes and at least one metallic thermal bonding material.

A semiconductor laser tuned with an acousto-optic modulator. The acousto-optic modulator may generate standing waves or traveling waves. When traveling waves are used, a second acousto-optic modulator may be used in a reverse orientation to cancel out a chirp created in the first acousto-optic modulator. The acousto-optic modulator may be used with standing-wave laser resonators or ring lasers.

In various embodiments, laser systems feature beam emitters thermally coupled to heat sinks comprising, consisting essentially of, or consisting of a metal-matrix composite of a thermally conductive metal and a refractory metal. At least a portion of the surface of the heat sink is treated to form a depleted region, and a diamond coating is deposited within and/or over the depleted region. The depleted region is substantially free of the thermally conductive metal or contains the thermally conductive metal at a concentration less than that of the body of the heat sink.

External cavity diode laser (ECDL) devices and methods for producing the same are described that allows ECDLs to be readily produced and configured to operate at a desired range of wavelengths, while allowing tunability of the output wavelength. One ECDL includes a laser gain chip including a gain medium, a first reflective surface at a first end of the gain medium, and a second surface at a second end of the gain medium opposite to the first reflective surface. The second surface has a facet that forms an angle approximately equal to Brewster's angle for light having a first wavelength. The ECDL further includes a diffraction grating positioned to receive light that passes through the second surface, to operate as a mirror in the external cavity diode laser, and to allow a portion of the light to be directed outside of the external cavity diode laser as output light.

A laser assembly (1210) for generating an assembly output beam (1212) includes a laser subassembly (1216) that emits a plurality of spaced apart first laser beams (1220A), a plurality of spaced apart second laser beams (1220B), a transform lens assembly (1244), a wavelength selective beam combiner (1246), and a path length adjuster (1299). The transform lens assembly (1244) collimates and directs the laser beams (1220A) (1220B) to spatially overlap at a focal plane of the transform lens assembly (1244). The path length adjuster (1299) is positioned in a path of the first laser beams (1220A), the path length adjuster (1299) being adjustable to adjust of a path length the first laser beams (1220A) relative to the second laser beams (1220B).

In various embodiments, a laser emitter such as a diode bar is cooled during operation via jets of cooling fluid formed by ports in a cooler on which the laser emitter is positioned. The jets strike an impingement surface of the cooler that is thermally coupled to the laser emitter but prevents direct contact between the cooling fluid and the laser emitter itself.

In various embodiments, laser resonator modules produce output beams via manipulation of input beams on opposite sides of the module. The input beams are emitted by one or more beam emitters that may be cooled using a liquid coolant cavity. The liquid coolant cavity may be isolated from optical elements utilized to manipulate the input beams, at least in part, by an isolation wall protruding from the base plate of the resonator module.