Methods and systems are provided for separating polarized UV light. In one example, a method may include passing polarized source light through a group of at least four prisms to collimate and separate a second-harmonic generation (SHG) beam from a pump beam. The separated SHG beam may then be further passed through a spatial filter to reduce spatial distribution.

A high harmonic generation assembly and method for generating high harmonic radiation. The assembly comprises a cavity configured to receive input radiation and increase the intensity of the input radiation inside the cavity for forming drive radiation suitable for use in high harmonic generation. The assembly further comprises an interaction region within the cavity at which, in use, a medium is present, the medium being configured to generate harmonic radiation by high harmonic generation when the drive radiation is incident thereupon, and an optical assembly configured to direct the drive radiation to pass through the interaction region, and comprising an output coupler comprising an aperture through which at least a part of the generated harmonic radiation is able to exit the cavity. The optical assembly is further configured to shape the drive radiation into a converging hollow beam before the drive radiation passes through the interaction region.

The present application relates to a light pulse signal processing system. A to-be-measured signal light source generates a to-be-measured signal light pulse, and the to-be-measured signal light pulse is transmitted to a cylindrical lens. The to-be-measured signal light pulse is converted into a to-be-measured signal light pulse having a spatial angle chirp by the cylindrical lens, and is outputted and is incident into a pair of long mirrors at different angles. The to-be-measured signal light pulse incident at different incident angles is delayed by the pair of long mirrors. A cluster of to-be-measured signal light pulses with a corresponding repetition rate is outputted to a beam combining mirror, and is combined with a cluster of reference light pulses by the beam combining mirror. A light signal analysis device analyzes the combined cluster of light pulses.

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.

An optical filter includes a substrate; a first mirror on the substrate; a cavity layer on the first mirror; and a second mirror on the cavity layer. Each of the first and second mirrors provide high reflection, low transmission and low absorption over a targeted stopband. The cavity layer defines a resonant transmission band within the targeted stopband with the resonant band wavelength depending on the optical thickness of the cavity layer. The cavity layer includes a material having a non-linear response to incident irradiance such that cavity absorption changes with irradiance and suppresses cavity resonance at high irradiance. The material having the non-linear response to the incident irradiance includes a two-dimensional (2D) material.

An optical resonator frequency comb comprising a main optical resonator being made of a resonator material, which has a third order nonlinearity and an anomalous resonator dispersion; a continuous wave (cw) laser configured for supplying continuous laser light into an optical waveguide, which is coupled with the main optical resonator. The cw laser, the optical waveguide and the main optical resonator are arranged for resonantly coupling the cw laser light into the main optical resonator for forming a single dissipative soliton circulating in the main optical resonator corresponding to the generation of a frequency comb. Furthermore, the optical resonator frequency comb further comprises an auxiliary optical element configured to induce a phase shift to a frequency comb component at the cw laser frequency to enhance the conversion efficiency of a generated frequency comb. The disclosure also relates to an associated method.

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.

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.

The invention relates to a frequency conversion arrangement (100) for optimising properties of a harmonic of a laser, in particular a beam profile and/or a long-term stability, the arrangement comprising:—a first non-linear crystal (X1), which is designed to convert a first wavelength (λ1) partially into a second wavelength (λ2); and—an optical unit, which in particular comprises at least one prism (P), which is designed in such a way as to influence the main axes (x1, y1, x2, y2) of the beam profiles of the first wavelength (λ1) and/or the second wavelength (λ2) differently; and—a second non-linear crystal (X2), which is designed in such a way as to generate a third wavelength (λ3) from the unconverted part of the first wavelength (λ1) and/or the second wavelength (λ2), the second non-linear crystal (X2) having an entry face (A1) and an exit face (A2), and the exit face (A2) running obliquely to the entry face (A1).