5 results about "Quasi-phase-matching" patented technology

This invention provides a multi-channel three-dimensional quasi-phase matching method and apparatus. The method includes: focusing fundamental frequency light through a microscope objective to obtain fundamental frequency light with a modified focusing state; incident the modified fundamental frequency light onto a nonlinear photonic crystal via normal incidence, and obtaining an outgoing second harmonic through the nonlinear photonic crystal; and finally, outputting multi-channel frequency-doubled light waves based on the outgoing second harmonic. This invention focuses fundamental frequency light onto a nonlinear photonic crystal via a microscope objective, changing the direction range of the incident fundamental frequency wave vector simply by altering the numerical aperture of the focusing objective. Combined with the spatial reciprocal lattice vector combination of the three-dimensional nonlinear photonic crystal, the quasi-phase matching condition is satisfied, achieving variable multi-channel frequency doubling. This invention achieves controllable multi-channel second harmonic generation without structural changes.

This invention provides a method, apparatus, device, and readable storage medium for generating a waveguide single-photon source, relating to the field of quantum optics. The method includes coupling a fundamental frequency light output from a laser into free space to form a spatial beam; adjusting the polarization state of the collimated spatial beam to match its polarization direction with the crystal axis of a fully encapsulated waveguide device; coupling the polarization-adjusted spatial beam into a polarization-maintaining transmission fiber to form fiber-optic transmission light; injecting the fiber-optic transmission light into the fully encapsulated waveguide device, and converting the fundamental frequency light into frequency-doubled light at a quasi-phase-matching operating temperature; outputting the frequency-doubled light from the fully encapsulated waveguide device and coupling it again into free space to form an output beam; and performing spatial spectral filtering and intensity attenuation on the output beam to reduce the average photon number per pulse to the single-photon level, obtaining a purified single-photon signal. This invention addresses the polarization matching problem between existing waveguide devices and fiber optic transmission links.

This application relates to the field of hyperspectral imaging technology, specifically to an imaging device and imaging method. The imaging device includes: an infrared light receiving unit, a pump light source, a wavelength tuning up-conversion unit, and a visible light detection unit; wherein the infrared light receiving unit is used to collect infrared light; the pump light source is used to generate pump light that undergoes frequency up-conversion with the infrared light; the wavelength tuning up-conversion unit is disposed in the optical path of the infrared light and the pump light to receive the infrared light and the pump light, and is configured to change the positions of the infrared light and the pump light within the wavelength tuning up-conversion unit, so that infrared light of different wavelengths satisfies the quasi-phase matching condition and undergoes frequency up-conversion with the pump light, thereby generating visible light of different wavelengths; the visible light detection unit is disposed in the optical path of the visible light; this imaging device utilizes the wavelength tuning up-conversion unit to perform frequency up-conversion of infrared light of different wavelengths, simplifying the optical path and improving system integration and reliability.

The application provides a high-efficiency synchronous triple-frequency laser generating device, which comprises a laser module, an optical intensity control module, a nonlinear crystal and a filter module, wherein the nonlinear crystal is a periodically poled crystal, and the synchronous cascade nonlinear frequency conversion of incident fundamental frequency light is completed to obtain triple-frequency light; compared with the prior art, by reasonably designing the domain length of the periodically poled crystal, on the basis of satisfying the quasi-phase matching of the sum frequency process, a certain phase mismatching amount is actively introduced for the frequency doubling process, so that the conversion efficiency of the frequency doubling light is moderately inhibited, the consumed fundamental frequency light is dynamically supplemented, and then the high-efficiency and high-stability triple-frequency laser output is realized.