An apparatus for emitting pulsed electromagnetic laser radiation includes a laser gain element; an optical arrangement defining a laser resonator and arranged to re-direct radiation emitted by the gain element along a beam path back onto the gain element, the optical arrangement comprising an output coupler configured to couple a portion of the radiation in the laser resonator out of the laser resonator; and, a pump arrangement configured to pump the laser gain element. The optical arrangement includes a mode locker placed in the laser resonator in the beam path, and a birefringent element placed in the laser resonator in the beam path.

A method for generating femtosecond vortex beams with high spatial intensity contrast, where a noncollinearly pumped HG beam femtosecond laser generates femtosecond HG beam and a cylindrical lens mode converter converts the femtosecond HG beam to femtosecond LG vortex beam. The HG beam femtosecond laser comprises a pump source, a gain medium, a saturable absorption mirror as mode-locker, and an output coupler with a noncollinear angle between the laser beam and the pump beam in the gain medium, which enables the laser to generate pure, order-tunable femtosecond HG beams. Femtosecond vortex beams obtained after the cylindrical lens converter have high-intensity-contrast, and are topological charge-tunable.

The present invention relates to a diode laser with external spectrally selective feedback. It is an object of the invention is to provide an external cavity diode laser with wavelength stabilization which allows an increased overall output power in the desired wavelength range. According to the invention, an external cavity diode laser arrangement is disclosed comprising: an active medium positioned inside an internal laser cavity (10), the internal laser cavity (10) comprising an exit facet (12) adapted for outcoupling laser radiation; an external frequency-selective element (14) positioned outside the internal laser cavity (10) and adapted for wavelength stabilization of the laser radiation; a beam divider (16) positioned outside the internal laser cavity (10) and adapted to divide the outcoupled laser radiation (B0) into a first beam (B1) extending along a first beam path (P1) and a second beam (B2) extending along a second beam path (P2), the first beam (B1) having higher radiant intensity than the second beam (B2) and the first beam path (P1) being different from the second beam path (P2); and an intensity control means to control the radiant intensity incident to the external frequency selective element (14); wherein the external frequency-selective element (14) and the intensity control means are arranged in the second beam path (P2). The intensity control means in the second beam path (P2) may comprise a polarization modifying means (18) and and a polarizer (20) in order to reduce thermal stress at the frequency-selective element (14).

A beam combining device and method for a Bragg grating external-cavity laser module has a plurality of side by side light-emitting modules that use a Bragg grating to perform wavelength locking. Output light of the modules is incident to a beam combining element after passing through a focusing optical element for beam combining, and light subjected to beam combining is reflected partially and transmitted partially under the effect of a light splitting element. A part is incident into a dispersion element at a diffraction angle of the element. Parallel light is formed under the effect of a conversion optical element. Spots of the light beams of corresponding wavelengths of the light-emitting modules are formed on an image acquisition mechanism. Whether the wavelengths of the corresponding light-emitting modules are locked is determined by whether there is a deviation between preset spots and spots formed by the module on the acquisition mechanism.

A laser resonator comprising a specially designed front mirror 32. The front mirror 32 together with a rear mirror form a resonator cavity. As well as having a resonator cavity reflective surface 42, the front mirror 32 also has an output coupling reflective surface 44 which forms a continuation of the resonator cavity reflective surface 42 and extends at an angle thereto so as to direct a beam laterally out of the cavity. The output coupling reflective surface 44 and the resonator cavity reflective surface 44 are joined by a “soft” rounded edge 40 of arcuate cross-section, this rounded transition suppressing diffraction ripples that would otherwise be generated if the edge were “hard”, i.e. sharp.

Coupled-cavity vertical cavity surface emitting lasers (VCSELs) are provided by the present disclosure. The coupled-cavity VCSEL can comprise a VCSEL having a first mirror, a gain medium disposed above the first mirror, and a second mirror disposed above the gain medium, wherein a first cavity is formed by the first mirror and the second mirror. A second cavity is optically coupled to the VCSEL and configured to reflect light emitted from the VCSEL back into the first cavity of the VCSEL. In some embodiments, the second cavity can be an external cavity optically coupled to the VCSEL through a coupling component. In some embodiments, the second cavity can be integrated with the VCSEL to form a monolithic coupled-cavity VCSEL. A feedback circuit can control operation of the coupled-cavity VCSEL so the output comprises a target high frequency signal.

A laser device includes: a first mirror and a second mirror that cause resonance of a plurality of beams having different wavelengths from one another; a diffraction grating that causes the beams that are incident from the first mirror with directions of beam central axes being different from one another to travel to the second mirror while aligning the beam central axes with one another, and causes the beams that are incident from the second mirror with the beam central axes being aligned with one another to travel to the first mirror while causing the directions of the beam central axes to be different from one another; and a housing unit housing a laser medium that is a medium through which the beams traveling between the first mirror and the diffraction grating pass, and has a discrete gain spectrum in which a peak occurs at each wavelength of the beams.

In a Q-switched solid-state laser having a resonator (3, 30) in the form of a linear resonator or a ring resonator having an active laser material (1) and at least one first and one second mirror (4, 5) and a resonator length (a) of less than 50 mm, preferably less than 25 mm, in the case of the configuration as a linear resonator and of less than 100 mm, preferably less than 50 mm, in the case of the configuration as a ring resonator, at least substantially only one longitudinal mode oscillates in the resonator (3). The resonator (3, 30) is in the form of an unstable resonator, with one of the mirrors (4, 5) being a gradient mirror.

A method for generating a spatially transformed optical output from a laser system, the method comprising: disposing a laser gain medium within a laser cavity structure; arranging an interferometric device to complete the laser cavity structure, wherein the interferometric device receives an input beam from laser oscillation in the laser cavity structure, splits the input beam into two sub-beams, and recombines the two sub-beams to provide an optical feedback beam to sustain laser oscillation; configuring the optical components that comprise the interferometric device to provide relative misalignment of the two sub-beams that are produced internally to the interferometric device; using at least a first output port of the interferometric device to provide an output beam of the laser system that due to the misalignment is a spatial transformation of the internal mode structure of the laser; and using at least a second output port of the interferometric device to provide the optical feedback beam to the laser cavity structure that sustains laser oscillation with a spatial structure that substantially preserves the internal mode structure of the laser. An apparatus which implements such a method is also provided.

UV laser devices, systems, and methods are shown and/or described herein. Included are a method, device or system for VECSEL and MECSEL lasers including both barrier-pumped and in-well pumped lasers. Also disclosed is a method of manufacturing gain chips for use in the lasers, arrangements of lasers, and selection of proper non-linear crystal (NLC) for use in the device.