A radio-frequency, RF, slab laser 10 with a Z-fold resonator cavity defined by an output mirror 32, a first fold mirror 34, a second fold mirror 36 and a rear mirror 30. The second fold mirror 36 is rotated by an adjustment angle away from the angle it would have if the mirrors were all plane mirrors and directed the round trip beam path by direct reflection. Moreover, the rear mirror 30 is rotated by an adjustment angle that is approximately twice the adjustment angle of the second fold mirror 36. These rotations of the rear mirror 30 and second fold mirror 36 suppresses parasitic mode paths that would otherwise exist.

A waveguide gas laser having a laser resonator cavity of a variable length is subjected to cyclical varying of the length of the cavity during generation of a laser beam a length variation amount sufficient to force a laser beam generated in the resonator cavity though a substantially complete optical longitudinal cavity mode at a rate operable to smooth at least one laser beam parameter variation. In this manner variation in the laser beam parameter is averaged by moving through at least a portion of an optical longitudinal cavity mode.

In various embodiments, the concentration and deposition of siloxane materials within components of laser systems, such as laser resonators, is reduced or minimized utilizing mitigation systems that may also supply gas having low siloxane levels into multiple different components in series or in parallel.

In various embodiments, cold-start times and performance of wavelength-beam-combining laser resonators are improved via adjustment of the operating wavelengths and/or temperature of beam emitters within the resonators.

The present application is directed to various architectures of a laser oscillator which include an optical element, reflective, refractive, or diffractive injection device for injection seeding and/or locking a laser oscillator.

A single longitudinal mode ring Raman laser including: a pump source outputting a pump light power, resonantly coupled to a first ring resonator; a optical measurement and piezo-actuator for stabilising the resonant coupling of the pump light power to a first ring resonator; a first ring resonator including a Raman gain medium, wherein the Raman gain medium receives the pump light power and undergoes Raman lasing generating resonated Stokes power at the corresponding Stokes output wavelength; the first ring resonator acting as a feedback loop for the pump light power and the resonated Stokes power and outputting a portion of the Stokes power as the laser output.

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.

A method or apparatus for narrowing the linewidth of a single mode laser is provided. The linewidth of a single mode laser is narrowed by injecting an optical feedback simultaneously into the first laser cavity mirror and the second laser cavity mirror of the single mode laser.

A method and system for injection-locking multiple optical amplifiers is disclosed. A master laser is employed to generate a continuous-wave output field. Optical modulators then produce first and second seed optical fields from the continuous-wave output field. The first and second seed optical fields provide an input to injection lock one or more optical amplifiers, optionally at different operating frequencies. Since the first and second seed optical fields are generated from the continuous-wave output field then the output fields of the optical amplifiers exhibit a high phase-coherence with each other and with the continuous-wave output field. Employing the first and second optical fields reduces the requirement to induce large frequency shifts on a single optical field. Techniques for phase-locking the output of the injection-locked laser systems are also provided to further reduce phase noise within the systems.

A laser system involving coupled distributed resonators disposed serially, with the lasing gain medium located in the main resonator and the output of that resonator being directed into a free space resonator, such that the main resonator output mirror is effectively the free space resonator. The distributed resonators end mirrors are retroreflectors. Interference occurs between light traveling towards the remote mirror of the free space resonator and light reflected therefrom, generating regions of high reflectivity. The coupling of the free space resonator to the regions of high reflectivity of the free space resonator enables the first resonator to lase efficiently, even though the true reflectivity of the main resonator output mirror outside of those regions is insufficient to enable efficient lasing, if at all. This coupled resonator structure enables lasing to occur with a high field of view and the high gain engendered by the high reflectivity regions.