21 results about "Gaussian mode" patented technology

The application discloses an optical module, comprising: a first laser emitting a first emission light of a Gaussian mode without a signal; a first coupler receiving the first emission light and dividing the first emission light into sub-emission light and first pilot light; a first modulator arranged at a first output port of the first coupler and used for phase modulation of the sub-emission light to generate sub-signal light; an optical fiber extension line arranged between a second output port of the first coupler and a vortex mode multiplexing module; and the vortex mode multiplexing module having a first input end connected with an output end of the first modulator and a second input end connected with the optical fiber extension line and used for converting the first pilot light and the sub-signal light into different vortex modes respectively and combining the vortex modes into a vortex signal emission light. The optical module provided by the application has the same frequency of signal light and pilot light in the emission light, and the signal light and the pilot light are transmitted in a vortex ring fiber in a vortex mode multiplexing mode, so that the communication quality and the communication capacity are improved.

The invention discloses a waist-adjustable structure-integrated square elbow of a DNP-NMR (Dynamic Nuclear Polarization Nuclear Magnetic Resonance) system transmission line. The waist-adjustable structure-integrated square elbow structurally comprises two corrugated waveguide structures, a right triangle cavity, a metal ellipsoid mirror surface and two external flange structures. The square elbow is installed in a transmission line, and the corrugated waveguide receives an HE11 mode coupled by a Gaussian fundamental mode from a gyrotron, so that long-distance transmission with small loss and low cross polarization is realized in a transmission line system; the right triangle cavity is connected with the two ends of the corrugated waveguide, an HE11 mode transmitted in the corrugated waveguide is recoupled into a Gaussian base mode at the position, the transmission direction of a wave beam is changed through the metal ellipsoid mirror surface, and the space flexibility of the transmission device is improved. Meanwhile, the metal ellipsoid mirror surface also adjusts the waist radius of the Gaussian fundamental mode so as to match the input requirement of the nuclear magnetic resonance system and keep the phase consistency of the original wave beam at the same time; the external flange structure is used for being tightly connected with other straight waveguide sections, and continuity and collimation of the cavity structure are guaranteed. Compared with a split type part, the integrated square elbow has the advantages that the assembly error of a construction system is obviously reduced, the machining difficulty is low, and the standardization degree is high. And meanwhile, the device can meet the requirements of a dynamic nuclear polarization nuclear magnetic resonance system on high-efficiency, stable, flexible-direction and long-distance transmission of Gaussian beams.

The application discloses a multi-mode vortex laser with adjustable order, comprising: a cavity lens coated with a laser wavelength anti-reflection film system, a first laser output mirror and a second laser output mirror, both of which are plane mirrors, and both of which are coated with a film system partially transmitting laser wavelength on one side and an anti-reflection film system for laser wavelength on the other side; a high-order Laguerre-Gaussian beam is focused by the cavity lens, and the focused beam waist positions of each-order Laguerre-Gaussian mode vortex light are separated under the action of spherical aberration of the cavity lens, and the higher the mode order and the larger the spot size, the closer the focused beam waist of the mode to the cavity lens; the positions of the first laser output mirror and the second laser output mirror are adjusted so as to be located at the waist positions of a certain mode, and the first laser output mirror and the second laser output mirror located at different positions provide feedback for two different-order Laguerre-Gaussian mode vortex lights, so that multi-mode vortex laser oscillation and output are formed.

The invention provides a three-dimensional object encryption and decryption method and system based on vortex light array regulation and control. The method comprises the steps that a three-dimensional model is constructed, and depth information and intensity information of the three-dimensional model are extracted; performing layering processing on intensity information through depth information of a three-dimensional object by utilizing a chromatography technology, and then combining with a sampling point array to generate a target image; a generated target image is modulated by using a random phase, then a reserved hologram containing depth information is generated by using angular spectrum diffraction, and then a selected hologram is constructed by combining a specific spiral phase index and a radial index. Further introducing an off-axis holographic technology and a digital blazed grating technology to splice the selected holograms, and modulating to generate a multiplexing encrypted hologram; and decryption processing is carried out on the multiplexing encryption hologram, and high-fidelity independent reconstruction of three-dimensional object information can be realized only by matching the Laguerre-Gaussian mode vortex light used during encryption, arrangement of the Laguerre-Gaussian mode vortex light and the depth of corresponding three-dimensional information. According to the three-dimensional object encryption and decryption method and system based on vortex light array regulation and control, interlayer crosstalk for decrypting three-dimensional information is effectively reduced, the accuracy of the three-dimensional information encryption and decryption system is improved, and the safety of the encryption system is remarkably enhanced.

The present application relates to the technical field of semiconductor process, and especially relates to a piezoelectric ultrasonic transducer and a preparation method thereof, which comprises a substrate, a piezoelectric layer formed on the front surface of the substrate, a back cavity formed by penetrating the substrate, a structure layer formed on the surface of the piezoelectric layer, the thickness of the structure layer being greater than the thickness of the piezoelectric film in the piezoelectric layer, and an anti-leakage sound layer arranged on the surface of the structure layer; a through groove is formed along the edge of the diaphragm, so that the diaphragm forms an external structure outside the diaphragm area and an internal structure in the diaphragm area, and the external structure and the internal structure are connected through a cantilever beam formed in the through groove. The preparation method comprises the following steps: preparing the substrate; growing the piezoelectric layer; etching the piezoelectric layer; growing the structure layer; etching the structure layer; and etching the substrate to form the back cavity. The present application uses silicon oxide as the structure layer, which can effectively reduce the resonant frequency; the cantilever beam can convert the PMUT from the Gaussian mode to the piston-like mode to improve the sensitivity, and can also provide good support.

The application discloses a method for measuring position of a point light source by using spatial mode decomposition multiplexing, and the principle of the method is based on orthogonal projection measurement in quantum detection theory. The method converts direct measurement of distribution of light intensity of the point light source in a coordinate space into measurement of weights of each Hermite-Gaussian mode. In the specific operation, only the complex conjugate of the complex amplitude of each Hermite-Gaussian mode needs to be encoded into a computer hologram. By replacing different computer holograms, the photon number at the optical axis of the first-order diffraction light is recorded, and then the weights of the to-be-measured light field in each Hermite-Gaussian mode can be obtained after normalization. Compared with the traditional measurement, only one pixel is needed to achieve optimal measurement.

The invention belongs to the technical field of ultrafast optics and light field regulation and control, and provides a digitalized adjustable off-axis pumping laser system which comprises a digitalized off-axis pumping module provided with a pumping source, a collimating lens, a spatial light modulator and a first focusing lens which are connected in sequence. The astigmatism resonant cavity is provided with an input coupling mirror, a gain medium, a concave reflecting mirror and an output coupling mirror which are connected in sequence, and the mode conversion module is provided with a plane reflecting mirror, a Dove prism, a second focusing lens and a cylindrical lens pair which are connected in sequence. According to the invention, the spatial light modulator is integrated in the off-axis pumping laser system to carry out digital modulation on the pumping light, so that the regulation and control precision of off-axis pumping is improved in order of magnitude; meanwhile, through programmable control of a spatial light modulator, in combination with efficient excitation of an astigmatism resonant cavity on a two-dimensional high-order Hermite-Gaussian mode and an astigmatism conversion function of a mode conversion module, a high-order structure light beam covering a whole Hermite-Laguerre-Gaussian mode space can be conveniently generated.

The invention discloses a refractive index measurement method and system based on the rotation angle of a superposed state Laguerre-Gaussian beam, and the method comprises the steps: generating a superposed state Laguerre-Gaussian beam, the wavefront phase of which comprises the phase components of a first Laguerre-Gaussian mode and a second Laguerre-Gaussian mode; enabling the superposed Laguerre-Gaussian beam to normally enter a medium to be measured; collecting light intensity distribution information of the light beam propagated through the to-be-measured medium, and determining a rotation angle of a light spot pattern generated by the superposition state Laguerre-Gaussian light beam according to the light intensity distribution information; and according to the rotation angle, the thickness of the to-be-measured medium and the mode parameters and the transmission characteristic parameters of the superposition state Laguerre-Gaussian beam, the refractive index of the to-be-measured medium is calculated based on the relationship between the rotation angle caused by Gelai phase shift and the refractive index. According to the invention, the calculation of the refractive index is converted into a rotation angle which is easy to accurately measure, a sample does not need to be contacted in the measurement process, and high-precision measurement of the refractive index is realized while the structure is simplified.

The invention relates to the technical field of lasers, in particular to a nanosecond ultraviolet solid laser in a Hermite-Gaussian mode. The laser comprises a pumping source, a pumping coupling device, a pumping end mirror, a gain crystal, a Q-switched crystal, a turning mirror, a frequency tripling crystal, a frequency doubling crystal and a tail end mirror. The pumping source, the pumping coupling device, the pumping end mirror, the gain crystal, the Q-switched crystal and the turning mirror are sequentially arranged along the light emitting direction of the pumping source; a frequency tripling crystal, a frequency doubling crystal and a tail end mirror are sequentially arranged along the refraction direction of the turning mirror; the pumping coupling device is internally provided with a lens group which is plated with a pumping light high-transmittance film, and the coupling ratio is 1: 1 to 1: 10; and the radius of curvature of the pumping end mirror is-5000 to 5000 mm. By adjusting the coupling proportion of a middle lens group of the pumping coupling device and the curvature radius of a pumping end mirror, the matching mode of the pumping light and the fundamental frequency light can be adjusted, so that the ultraviolet laser in a high-order Hermitian-Gaussian mode is obtained.

The application discloses an optical module, comprising: a receiving optical fiber, receiving vortex receiving light. A vortex mode demultiplexing module is connected with the receiving optical fiber, used for splitting and converting the first sub-receiving signal light and the receiving pilot light into Gaussian mode. A first coherent receiver is connected with the first output port of the vortex mode demultiplexing module through the first input port, and connected with the second output port of the vortex mode demultiplexing module through the second input port, used for mixing and detecting the sub-receiving signal light and the first sub-pilot light into the first electrical signal. The application obtains the Gaussian mode receiving pilot light and the receiving signal light by demultiplexing the vortex receiving light, and the receiving pilot light is used as the local oscillator light to realize self-homodyne coherent transmission, eliminating the influence of frequency offset and phase noise, without complex carrier recovery algorithm, reducing the complexity, power consumption and cost of the coherent detection system, and breaking through the limitations of high power consumption, high complexity and high cost of the traditional coherent detection.

The present application relates to the technical field of high-power millimeter wave, and particularly relates to a high-power millimeter wave quasi-optical matching unit. The technical scheme comprises a matching unit body, corrugated circular waveguides and circular waveguides are arranged on the two sides of the unit body respectively, the matching unit body comprises an input window, a phase correction mirror, an output window, a support adjusting assembly and a plurality of load porcelain tubes, the phase correction mirror comprises a reflecting mirror one and a reflecting mirror two, the phase correction mirror is designed by using an adaptive optimization iterative algorithm, efficient conversion of the high-power gyrotron quasi-Gaussian mode beam to a TEM11 mode beam is realized, energy utilization is improved, and beam transmission indexes are guaranteed; six support adjusting assemblies are arranged, the mirror and the radiation inlet position can be finely adjusted, process errors and beam deviations can be adapted, system adaptability and fault tolerance are improved, and output beam parameter stability is ensured.

The invention discloses an optical fiber mode multiplexing quasi-homochromatic marginal light suppression super-resolution photoetching system. The system aims to solve the problem of nonlinear dispersion of femtosecond laser in optical fiber transmission and the problem of poor stability of annular suppression light spots generated by a traditional spatial light path. The core lies in three modules: firstly, a fiber-grating-fiber dispersion compensation module (a large-mode-field-diameter photonic crystal fiber is combined with a grating pair) is adopted, so that broadening of femtosecond pulses is effectively inhibited, and high-peak power required by inscribing is ensured; the optical fiber generation of an incoherent Hermite-Gaussian mode is realized, annular suppression and Gaussian excitation light spots (collectively called PPI light spots) with stable intensity distribution are synthesized, and the anti-interference capability of the system is remarkably improved. And parallel direct writing is realized through the multi-channel optical fiber array and the high-speed scanning module. According to the invention, the PPI light spot array with low dispersion and high stability is generated by using the optical fiber, the expansibility is good, and high-precision and high-flux three-dimensional super-resolution photoetching processing can be realized.

The invention discloses a high-order Hermite-Gaussian and Enth-Gaussian mode intracavity cooperative regulation and control device which comprises a pumping source, a focusing optical device, a plane input mirror, a gain medium, a plane-concave output cavity mirror and a detection assembly are sequentially arranged at the output end of the pumping source, and a plane-concave resonant cavity is formed among the plane input mirror, the gain medium and the plane-concave output cavity mirror. The pumping source outputs pumping light, and the focusing optical device focuses the pumping light to the gain medium; a multi-axis optical platform is arranged at the lower ends of the gain medium and the plano-concave output cavity mirror, the plano-concave output cavity mirror translates along x and y directions of the orthogonal multi-axis optical platform to introduce off-axis displacement, and the gain medium rotates around a pitch axis of the multi-axis optical platform to break cylindrical symmetry of a resonant cavity so as to introduce controllable astigmatism; the detection assembly is used for capturing a laser transverse mode pattern. According to the technical scheme, the high-order Hermite Gaussian mode laser cavity and the high-order Hermite Gaussian mode laser cavity which are compact in structure, low in loss, flexible in mode regulation and control and high in parameter adaptability are directly generated, regulated, controlled and mutually converted in the laser cavity.

The application discloses an energy coupling device between a metal circular waveguide and a terahertz dielectric circular waveguide, comprising a metal circular waveguide, a dielectric hemisphere and a dielectric cylinder. The dielectric hemisphere and the dielectric cylinder are arranged on the right side of the metal circular waveguide; the dielectric hemisphere is located in the metal circular waveguide; and the dielectric cylinder is connected with the end face on the right side of the metal circular waveguide. An electromagnetic signal in a quasi-Gaussian HE11 mode is input into the metal circular waveguide through an input end of the energy coupling device, and after energy coupling through the dielectric hemisphere, the coupled electromagnetic signal is transmitted into the terahertz dielectric circular waveguide through an output end of the energy coupling device by the dielectric cylinder. The energy coupling device can ensure high coupling efficiency, wide working bandwidth and high compactness of the structure, and can also reduce the processing and assembly difficulty of the structure.

The invention discloses a rotating Doppler velocity measurement method and device based on Gaussian mode emission and multimode optical fiber receiving, belongs to the technical field of photoelectric detection and sensing, and aims to solve the technical problems of complex system, high cost and poor robustness caused by dependence on active orbital angular momentum modulation and filtering in the conventional rotating Doppler velocity measurement technology. The method comprises the following steps: emitting a single-mode Gaussian beam to a rotating target; a multimode optical fiber is used for receiving scattered echoes, and a plurality of OAM modes are excited; detecting an optical signal output by the multimode optical fiber to obtain a beat frequency time domain signal generated by multimode interference; and performing spectrum analysis on the signal to obtain a rotating Doppler spectrum containing spectrum peaks at equal intervals, and calculating the rotating speed according to the spectrum peak interval. The device comprises a laser emitting module, a light receiving and converting module and a signal processing module which are connected in sequence. According to the invention, active OAM modulation and filtering are not needed, and rotation speed measurement can be realized by using a conventional optical device.

The application provides a multi-core OAM mode demultiplexer and method based on spiral transformation reverse design, the application sets an initial spiral coordinate transformation phase plate for reverse design optimization, which is an optical transformation phase plate, a phase correction phase plate and an elliptical lens phase plate; input vortex modes are sequentially propagated through the three phase plates and evolved into output spatially separated Gaussian-like modes, the phase distribution of the three phase plates is optimized by a wavefront matching method, the average overlap integral of the output Gaussian-like mode and the ideal Gaussian mode is taken as an objective function, and iteration is performed until convergence, so that the corresponding three phase plates optimized by reverse design are obtained, the number of modes supported by the photon orbital angular momentum mode demultiplexer after reverse design optimization is improved by nearly one time, and the output beam quality is improved; the application is beneficial to compatibility of 19-core OAM fiber communication, and has important significance for development of the field of super-large capacity dense OAM space division multiplexing.

The utility model provides a refractive index step type elliptical core few-mode optical fiber, which is composed of a pure silicon dioxide elliptical fiber core with refractive index step distribution, a trench region and a cladding, and the ellipticity rho is equal to ax / ay equal to 1.6; spatial mode degeneracy is broken, mode-preserving operation of eight Hermite-Gaussian modes is realized, and the method has the advantages of low loss, low crosstalk and the like.

The application belongs to the technical field of ultrafast optics and light field regulation, and provides a digital adjustable off-axis pumping laser system, which comprises a digital off-axis pumping module with sequentially connected pumping source, collimating lens, spatial light modulator and first focusing lens, astigmatic resonant cavity with sequentially connected input coupling mirror, gain medium, concave mirror and output coupling mirror, and mode conversion module with sequentially connected plane mirror, dove prism, second focusing lens and cylindrical lens pair. The application realizes order of magnitude improvement in the regulation accuracy of off-axis pumping by integrating the spatial light modulator to digitally modulate the pumping light in the off-axis pumping laser system. Meanwhile, through programmable control of the spatial light modulator, combined with efficient excitation of two-dimensional high-order Hermite-Gaussian mode by the astigmatic resonant cavity and the astigmatic transformation function of the mode conversion module, high-order structured light beams covering the entire Hermite-Laguerre-Gaussian mode space can be conveniently generated.

The application discloses a vertical cavity surface emitting laser, and relates to the technical field of semiconductor devices.The vertical cavity surface emitting laser comprises a substrate, a bottom electrode, a bottom reflector, a multi-quantum well layer, a top reflector and a top electrode which are arranged in layers; and the top reflector is provided with a current limiting layer, wherein the current limiting layer comprises a current limiting area and a plurality of current channels defined by the current limiting area; the plurality of current channels are arranged at intervals; the plurality of current channels have low resistance; and the top electrode is provided with a plurality of through holes corresponding to the plurality of current channels one by one.The vertical cavity surface emitting laser can balance the current density of the current channels, so that the light spot mode of the vertical cavity surface emitting laser tends to be a Gaussian mode.

The invention discloses a manifold embedded Gaussian sputtering method and system for a non-attitude sparse input scene, and the method specifically comprises the steps: encoding an input image, employing SPENet to aggregate multi-scale features of three stages, employing a large-kernel expansion convolution (LDC) module and a skipping attention feature interaction SAFI module, and learning rich hierarchical feature representation; t-DSGE is embedded in a t-distribution dual space Gaussian mode, and alignment between the space and the visual attribute space is restrained; local linear embedding regularization LLER is used to promote local geometric smoothness and uniformity in Gaussian distribution; a neighborhood Gaussian densification (NGD) strategy is used, new gauss are inserted to densify a dense and sparse region, and components are jointly optimized with luminosity, geometry and global consistency to ensure stable convergence on unseen viewpoints and improve rendering quality. According to the method, the Gaussian sputtering local detail representation capability of the attitude-free sparse input scene is improved, and the spatial integrity and geometric continuity of the reconstructed 3D scene are improved.

A silicon-lithium niobate double-layer grating coupler comprises a silicon substrate layer, a silicon dioxide isolation layer, a lithium niobate layer, a silicon dioxide buffer layer, a silicon waveguide layer and an upper cladding layer. The grating coupler structure comprises a grating diffraction area, a focusing type spot size conversion area and a waveguide area. The waveguide region and the focusing type spot size conversion region adopt thin silicon structures to form a silicon-silicon oxide-lithium niobate hybrid waveguide, and most of energy is constrained in lithium niobate; the diffraction area of the grating adopts a thick silicon structure, and the characteristic size of the diffraction area is 220nm. The double-layer structure enhances the interference phase length of an etching area and an unetched area of the grating, and further improves the coupling efficiency. Secondly, the structure reduces back reflection by eliminating Bloch mode mismatch between the etched region and the non-etched region. According to the invention, the chirp structure is utilized to regulate and control the diffraction mode field of the grating, so that the diffraction mode field is matched with the Gaussian mode field of the single-mode fiber, the mismatch between the diffraction field of common uniform grating exponential attenuation and the Gaussian mode field is overcome, and the coupling efficiency of the grating is further improved. Compared with the prior art, the device has the advantages of high coupling efficiency, CMOS (complementary metal oxide semiconductor) process compatibility and the like, the device is integrated on a silicon-lithium niobate heterogeneous wafer and can be directly integrated with other silicon-based devices, lithium niobate modulators and other devices, and the double-layer silicon waveguide structure can be popularized to other heterogeneous integration platforms.