An object is to provide, for example, a method for manufacturing an optical wavelength conversion device having a structure that enables efficient formation of crystal regions on the surface of, or inside, an amorphous material. An amorphous main body is intermittently irradiated with a first laser beam for generating a high-density excited electron region inside the main body and a second laser beam for heating the high-density excited electron region, with respective focus regions of the first and second laser beams overlapping each other. During the intermittent irradiation with the first and second laser beams, the relative position of the main body and the overlapping focus region of the first and second laser beams are varied. This enables part of the main body where the overlapping focus region moves to serve as a heat source for forming a crystal region.

An optical parametric oscillator (OPO) for generating an optical frequency comb is described. The OPO is configured to control cavity dispersion such that the OPO is able to generate extended signal and/or idler spectra in response to a continuous-wave pump. Each spectrum includes multiple modes that are substantially equispaced with substantially the same frequency spacing.

Beam adaptation devices are disclosed for variable-astigmatic adjustment of electromagnetic radiation propagating along a beam axis of the beam adaptation device. The devices include a first astigmatism lens unit, which provides at least one first lens tiltable with respect to the beam axis for astigmatism adjustment, a divergence matching lens unit with a second lens for adjusting the divergence, wherein the distance between the second lens and the first lens along the beam axis is adjustable, and a second astigmatism lens unit with at least one third lens tiltable with respect to the beam axis for astigmatism adjustment. To adjust the magnitude of the electromagnetic radiation on the third lens, the distance between the second lens and the third lens along the beam axis is adjustable. The beam adaptation device can be used, for example, for astigmatic pre-compensation in frequency conversion.

A waveguide is provided including first and second diffraction gratings and a phase-matching region conterminous with the first and second diffraction gratings and disposed in an optical path between the gratings. For an optical beam propagating along the optical path, the first grating adds a first phase shift to the optical beam reflecting from the first grating, the second grating adds a second phase shift to the optical beam reflecting from the second grating, and the phase-matching region adds a matching phase shift to the optical beam reflecting from the phase-matching region. The matching phase shift is between minimum and maximum values of the first and second phase shifts.

A pump beam (12) is pre-tilted by subjecting the pump beam to pulse-front-tilting, the thus obtained tilted-pulse-front pump beam is then coupled into the nonlinear optical medium. THz radiation is generated in the optical medium by nonlinear optical processes, in particular by optical rectification, by the pump beam. A pulse-front-tilt of the pump beam satisfying the velocity matching condition of v.sub.p,cs cos()=v.sub.THz,f is induced as a sum of a plurality of pulse-front-tilts separately induced as a partial pulse-front-tilt of the pump beam in subsequent steps. The last step of pulse-front-tilting of the pump beam is performed by coupling the pump beam into the nonlinear optical medium through a stair-step structure (40) formed in an entry surface (51) of the nonlinear optical medium which forms an angle () of a given non-zero size with an exit surface (52) of said nonlinear optical medium.

Apparatus include an optical cavity including an optical coupling portion situated to couple an optical signal input field to an intracavity optical signal field and an optical control input field to an intracavity optical control field, wherein the optical cavity includes a nonlinear optical medium that mediates a selective exchange of at least one predetermined temporal mode between the intracavity optical signal field and an intracavity optical register field based on a nonlinear phase-matched interaction between the intracavity optical signal, control, and register fields and selectable field characteristics of the optical control input field.

A light source device according to the present disclosure that is provided with a semiconductor laser unit configured to emit excitation light of a prescribed wavelength, a wavelength conversion unit configured to amplify the excitation light by causing the excitation light to resonate and generate output light of a different wavelength from the excitation light using a prescribed non-linear crystal, the wavelength conversion unit including a first optical path for amplifying the excitation light, and a second optical path for generating the output light, a first servo mechanism configured to control an optical path length of the first optical path, and a second servo mechanism configured to control an optical path length of the second optical path.

A method of making a quasi-phase-matching (QPM) structure comprising the steps of: applying a pattern to a substrate to define a plurality of growth regions and a plurality of voids; growing in a growth chamber a crystalline inorganic material on only the growth regions in the pattern, the crystalline inorganic material having a first polarity; applying an electric field within the growth chamber containing the patterned substrate with the crystalline inorganic material, wherein the electric field reaches throughout the growth chamber; and growing a crystalline organic material having a second polarity in the voids formed in the inorganic material under the influence of the electric field to influence the magnitude and the direction of the second polarity of the crystalline organic material, wherein the second polarity of the crystalline organic material is influenced to be different from the first polarity of the crystalline inorganic material in magnitude and/or direction.

Systems and methods are provided for optimizing the energy output of a laser system, such as a Light Detection and Ranging (LIDAR) system, by allowing the laser system to be tuned while the laser is in operation. For example, in an embodiment, a sensor, such as a photoresistor, is used to perform a scan to determine whether turning the crystal will result in increased energy. Crystal turners, such as servo motors, can be used to turn the crystal until the energy stops increasing.

A nonlinear wave mixing system with grating assisted phase matching is provided. The system includes a pump laser and a nonlinear waveguide. The pump laser is used to generate pump light at a select wavelength. The nonlinear waveguide is configured to generate produced light from the pump light that is directed into the nonlinear waveguide. The nonlinear waveguide includes at least one backward grating that is configured to diffract the produced light in a backward direction relative to a direction the produced light travels in the nonlinear waveguide to reach the backward grating. The backward grating having a grating momentum that generates counter-propagating phase matching in the produced light.