Methods, systems and apparatus are disclosed for delivery of pulsed treatment radiation by employing a pump radiation source generating picosecond pulses at a first wavelength, and a frequency-shifting resonator having a lasing medium and resonant cavity configured to receive the picosecond pulses from the pump source at the first wavelength and to emit radiation at a second wavelength in response thereto, wherein the resonant cavity of the frequency-shifting resonator has a round trip time shorter than the duration of the picosecond pulses generated by the pump radiation source. Methods, systems and apparatus are also disclosed for providing beam uniformity and a sub-harmonic resonator.

A laser ignition system, in particular for an internal combustion engine, including a vertical emitter and a laser-active crystal, the laser-active crystal being doped in at least some areas using ytterbium, the ytterbium-doped area having a length of 200 m to 7000 m. The monolithic laser is based on a YAG or LuAG host crystal having 3 differently doped areas: a laser-active ytterbium-doped area, an undoped area which determines the resonator length and therefore the pulse duration, and a chromium-doped or vanadium-doped area for the passive Q-switch. The resonator is delimited by 2 mirrors.

A fiber gain medium provided by a rare-earth doped fiber (10) is contained in a first resonant cavity by end reflectors (12, 18). The reflector (12) is wavelength selective to limit the frequency band of the first resonant cavity. The first resonant cavity also contains a second resonant enhancement cavity (16) with multiple transmission bands lying within the first resonant cavity's frequency band. Multiple standing wave modes of the first resonant cavity lie within both the frequency band of the first resonant cavity and the transmission bands of the second resonant cavity, and it is these standing wave modes that support laser action when the rare-earth doped fiber is suitably pumped by pump lasers (40).

An apparatus for generating and amplifying laser beams at approximately 1 micrometer wavelength is disclosed. The apparatus includes an ytterbium-doped gain-crystal pumped by an ytterbium fiber-laser. The fiber-laser enables a pump wavelength to be selected that minimizes heating of the gain-crystal. The apparatus can be configured for generating and amplifying ultra-fast pulses, utilizing the gain-bandwidth of ytterbium-doped gain-crystals.

A light pulse generator is provided, comprising a linear resonator cavity supporting the back-and-forth propagation of cavity light pulses therein. The linear resonator cavity has a linear optical path apt to induce a spectral broadening of the cavity light pulses. The light pulse generator includes first and second cavity-end filters disposed at opposite extremities of the linear optical path, and at least one optical gain region positioned in the linear optical path. A light output is optically coupled to the first cavity-end filter. The light pulse generator also includes a pulse-recycling filter optically coupled to the second cavity-end filter and having a reflectivity profile centered on a third wavelength. The pulse-recycling filter is configured to receive at least a spectral portion of the cavity light pulses and reflect recycled light pulses for a single pass through the at least one optical gain region and for extraction through the light output.

Various embodiments provide a high-efficiency and directional non-resonant laser using a scattering cavity and a method of manufacturing the same. According to various embodiments, the non-resonant laser may include a gain medium unit in which a scattering cavity and an entrance communicating with the scattering cavity are provided, and a pumping and supply unit configured to supply pumping light to an inside of the scattering cavity. The gain medium unit may be implemented to be excited by the pumping light on the inside of the scattering cavity and to output emission light through the entrance. According to various embodiments, the gain medium unit may weaken the pumping light while reflecting the pumping light on the inside of the scattering cavity, and may amplify the emission light while reflecting the emission light on the inside of the scattering cavity.

A light concentrator includes two light reflectors connected to each other with an angle on one end to form a widening wedge-shaped structure with an opening aperture on the opposite end. At least one of the light reflectors is an active mirror device that includes a substrate having a smooth reflective surface, and a plurality of light-emitting elements disposed on the smooth reflective surface. The light emitted by the light-emitting elements is reflected, amplified, and concentrated toward the opening aperture for pumping a crystal to generate laser radiation. The widening wedge-shaped structure of the light concentrator may be filled with luminescent materials to convert the light of a wavelength from the light-emitting elements into luminescence light of another wavelength for pumping a crystal to generate laser radiation.

[Problem] An excitation light output is improved without generating heat and lowering an operational life. [Solution] A laser element includes: a laminated semiconductor layer that includes a first reflection layer used for light of a first wavelength and an active layer that performs surface light emission at the first wavelength; a second reflection layer that is disposed closer to a light emission surface side than the laminated semiconductor layer, and is used for the light of the first wavelength; and a polarization splitting element that individually resonates and multiplexes each of orthogonal polarized beams included in light emitted from the laminated semiconductor layer between the first reflection layer and the second reflection layer.