An electromagnetic radiation frequency, or equivalent wavelength, converter, the converter including a nonlinear optical component or part having or consisting of a predetermined nonlinear optical material, and a guiding module. The guiding module has a predetermined geometry defining or controlling an effective refractive index of the guiding module, and is configured to receive and guide pump light resulting in a guided pump beam. The nonlinear component or part is bonded with or joined to the guiding module. The bonding is configured to allow at least a part of the guided pump beam to overlap and/or evanescently couple into the nonlinear optical material, and the nonlinear optical component or part is configured to convert the guided pump beam in the nonlinear optical material to an un-guided signal mode radiated as an output light signal at a different frequency or an equivalent wavelength.

Nonlinear on-chip optical devices using AlScN are described herein. In one aspect, an optical component having nonlinear characteristics can include a first substrate defining a refractive index; and a nonlinear layer, the nonlinear layer disposed on the first substrate, the nonlinear layer comprising an amount of scandium (Sc), and the nonlinear layer defining a refractive index that is higher than the refractive index of the first substrate.

The present invention describes a laser system for eliminating astigmatism to produce an elliptical laser beam that has an ellipticity between about 0.9 to 1.0. The laser system described herein allows for increased conversion efficiency and output powers. on-linear optical elements in the laser system eliminate astigmatism. The laser system comprises one or more cavities with wavelength splitters that act as dual-minor chambers for single-pass light transmission through the non-linear optical elements to reduce cavity size or as beam splitters for double-pass light transmission through the non-linear optical elements to increase laser output power. The laser system may also include a birefringent filter and/or etalon in the first cavity for polarization and wavelength tuning. The laser system may also generate a high-power, deep-ultraviolet laser output. The laser system may also be devoid of curved mirrors and non-normal incidence reflection to eliminate astigmatism.

It discloses a system and a method for generating heralded single photons, wherein the system comprises a high-quality optical ring cavity, a PPKTP nonlinear crystal, a polarization beam splitter, a dichroic mirror, a light filtering device, a reflector module, an atomic vapor cell and a single photon detector, wherein: the high-quality optical ring cavity is formed by a first plano-concave reflector, a second plano-concave reflector, a third plano-concave reflector and a fourth plano-concave reflector; the PPKTP nonlinear crystal and the polarization beam splitter are positioned in an optical path between the first plano-concave reflector and the second plano-concave reflector; the dichroic mirror is positioned in an optical path behind a reflecting end of the polarization beam splitter.

A frequency conversion laser system is configured with a single mode (SM) laser source outputting a pulsed pump beam at a fundamental frequency and a nonlinear optical system operating to convert the fundamental frequency sequentially to a second harmonic (SH) and then third harmonic (TH). The nonlinear optical system includes an elongated SHG crystal traversed by the SM pulsed pump beam which generates the SH beam. The SHG crystal has an output surface inclined relative to a longitudinal axis of the SHG crystal at a first wedge angle different from a right angle. The nonlinear optical system further has an elongated THG crystal with an input surface which is impinged upon by a remainder of the pump and SHG beams which propagate through the THG crystal at a walk-off angle therebetween to generate a third harmonic (TH) beam, the input surface of the THG crystal being inclined to a longitudinal axis of the THG crystal at a second wedge angle. The output and input surfaces of respective SHG and THG crystals are inclined so as to minimize the walk-off angle between SH and IR pointing vectors in the THG crystal thereby improving the conversion efficiency and TH output beam's ellipticity.

Systems and methods for measuring or inspecting semiconductor structures using broadband infrared radiation are disclosed. The system may include an illumination source comprising a pump source configured to generate pump light and a nonlinear optical (NLO) assembly configured to generate broadband IR radiation in response to the pump light. The system may also include a detector assembly and a set of optics configured to direct the IR radiation onto a sample and direct a portion of the IR radiation reflected and/or scattered from the sample to the detector assembly.

A wavelength conversion device includes a second-order nonlinear optical medium with a polarization inversion structure, wherein the wavelength conversion device performs wavelength conversion between three wavelengths according to a relationship of 1/λ.sub.1=1/λ.sub.2+1/λ.sub.3, a polarization inversion period Λ of the polarization inversion structure is divided into 2a regions, and when the 2a regions divided from the polarization inversion period Λ each has a width ratio of an inverted region and a non-inverted region of r to 1−r (where 0≤r≤1), a ratio value r is set such that, when one period in phase of a sine function from 0 to 2π is divided into 2a regions, a value of the sine function in a center of each divided region is (1−2r)±0.1.

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.

A photon source for generating entangled photons includes a pump laser, and 4-N, N-dimethylamino-4′-N′-methyl-stilbazolium-tosylate (DAST) crystals, the pump laser pumping the DAST crystals with pump photons to generate a stream of pairs of entangled photons, each pair comprising a signal photon and an idler photon.

A method of performing heteroepitaxy comprises exposing a substrate to a carrier gas, a first precursor gas, a Group II/III element, and a second precursor gas, to form a heteroepitaxial growth of one of GaAs, AlAs, InAs, GaP, InP, ZnSe, GaSe, CdSe, InSe, ZnTe, CdTe, GaTe, HgTe, GaSb, InSb, AlSb, CdS, GaN, and AlN on the substrate; wherein the substrate comprises one of GaAs, AlAs, InAs, GaP, InP, ZnSe, GaSe, CdSe, InSe, ZnTe, CdTe, GaTe, HgTe, GaSb, InSb, AlSb, CdS, GaN, and AlN; wherein the carrier gas is H.sub.2, wherein the first precursor is HCl, the Group II/III element comprises at least one of Zn, Cd, Hg, Al, Ga, and In; and wherein the second precursor is one of AsH.sub.3 (arsine), PH.sub.3 (phosphine), H.sub.2Se (hydrogen selenide), H.sub.2Te (hydrogen telluride), SbH.sub.3 (hydrogen antimonide), H.sub.2S (hydrogen sulfide), and NH.sub.3 (ammonia). The process may be an HVPE (hydride vapor phase epitaxy) process.