A mid-infrared broadband laser including: a femtosecond laser configured to generate a near-infrared light; nonlinear waveguide configured to broaden and/or shift a spectrum of the light from the femtosecond laser; and a nonlinear medium configured to generate a broadband light by mixing spectral components of the output from the non-linear waveguide. Optionally, at least one dispersion compensation element may be placed between the femtosecond laser and the nonlinear waveguide and/or between the nonlinear waveguide and the nonlinear medium.

A nonlinear crystal grating assembly including two integral nonlinear crystal grating structures having inverted crystal axes and having parallel spaced-apart mesas with predetermined mesa widths arranged such that, when assembled in an interdigitated configuration, the mesas of the two grating structures form an alternating grating pattern that is aligned with a propagation direction of input light, thereby creating a periodic structure for quasi-phase-matching (QPM). The nonlinear crystal grating structures are formed using strontium tetraborate, lithium triborate or another nonlinear crystal material. The nonlinear crystal grating assembly is utilized in a laser assembly in which fundamental wavelengths are doubled and/or summed using intermediate frequency conversion stages, and then a final frequency converting stage utilizes the nonlinear crystal grating assembly to double or sum one or more intermediate light beam frequencies to generate laser output light at high power and photon energy levels. A method and inspection system are also described.

In some embodiments, a device for generating mid-infrared radiation is provided. The device may include a thin film quadratic nonlinear waveguide formed on a mid-infrared transparent cladding by a thin film material of a predetermined film thickness, the waveguide having a predetermined etch depth and a predetermined top width. At least one of the predetermined film thickness, the predetermined etch depth, and the predetermined top width may be tuned for the device to generate a coherent idler wave as a mid-infrared radiation from a fixed pump wave and a tunable signal wave.

Improved efficiency for nonlinear optical interactions is provided by using strongly confining waveguides for simultaneous imposition of dispersion design constraints at two or more dispersion orders. Quasi-phase-matching allows for phase-matching to be accomplished independently of the waveguide design, which helps provide sufficient design freedom for the dispersion design.

A method for fabricating an optical waveguide comprises: providing a sample of lithium niobate doped with magnesium oxide and having at least one grating of periodic domain inversion defined therein; applying a layer of metallic zinc to a surface of the sample over the at least one grating using sputter deposition; heating the sample in an atmosphere of pure oxygen to cause the zinc to indiffuse into the lithium niobate to form a waveguiding layer of increased refractive index under the surface of the sample; and using a dicing blade to cut two substantially parallel channels along a length direction of the at least one grating, to define a ridge waveguide between the two channels.

Provided is a wavelength conversion element capable of achieving highly efficient wavelength conversion, without relying on a method of applying electric fields. A wavelength conversion element is formed of a second-order nonlinear optical crystal and has a z-axis, running along a direction of spontaneous polarization, within a substrate plane. The wavelength conversion element includes a waveguide in which, when a plurality of circles having their centers on a straight line parallel to the z-axis and having the same radius are depicted so that circumferences of the plurality of circles contact each other, semicircular waveguides corresponding to one semicircles of the circumferences with the straight line as a boundary, are alternately connected.

A cylindrical electrode module of a fiber optic laser system includes an inner cylinder having an inner repeating pattern of longitudinally-aligned positive and negative electrodes on an outer surface of the inner cylinder. The cylindrical electrode mode includes an outer cylinder that encloses the inner cylinder. The outer cylinder that has an outer repeating pattern of longitudinally-aligned negative and positive electrodes on an inner surface of the inner cylinder that are in corresponding and complementary, parallel alignment with the positive and negative electrodes of the inner repeating pattern on the outer surface of the inner cylinder. The cylindrical electrode module includes an optical fiber having an input end configured to align with and be optically coupled to a high power pump laser. The optical fiber is wrapped around the inner cylinder within the outer cylinder to form a cylindrical fiber assembly. The electrodes are activated to achieve quasi-phase matching.

A fiber laser system includes a high power pump laser, an optical fiber that is aligned to receive output from the high power pump laser. The fiber laser system includes a first pair of orthogonally opposed, periodic electrode structures longitudinally aligned on opposite first and second sides of the optical fiber. The fiber laser system includes a controller that is communicatively coupled to the first pair of periodic electrode structures. The controller performs variable period poling of the first pair of periodic electrode structures to achieve quasi-phase matching (QPM).

Improved efficiency for nonlinear optical interactions is provided by using strongly confining waveguides for simultaneous imposition of dispersion design constraints at two or more dispersion orders. Quasi-phase-matching allows for phase-matching to be accomplished independently of the waveguide design, which helps provide sufficient design freedom for the dispersion design.

A mid-infrared broadband laser including: a femtosecond laser configured to generate a near-infrared light; nonlinear waveguide configured to broaden and/or shift a spectrum of the light from the femtosecond laser; and a nonlinear medium configured to generate a broadband light by mixing spectral components of the output from the non-linear waveguide. Optionally, at least one dispersion compensation element may be placed between the femtosecond laser and the nonlinear waveguide and/or between the nonlinear waveguide and the nonlinear medium.