32 results about "Kerr effect" patented technology

A method includes acquiring and characterizing multiple laser beams. The method includes tracking the acquired laser beams. The method includes controlling a beam of the acquired laser beams. The method includes implementing an adaptive learning detection algorithm to identify and track a unique optical signature from at least one of the acquired laser beams. The method includes steering at least one laser beam towards a target based on the acquired laser beams. The method includes changing one or more optical properties of a beam steering unit to steer the at least one laser beam towards the target, including one or more of the following: inducing a Pockels effect on the at least one beam by applying an electric field; tuning Spatial Light Modulators; tuning a metamaterial structure; inducing a diffraction grating; and modifying an output angle of the at least one beam.

The invention relates to a miniature stress detector, which comprises a light emitting assembly, a detection head and a light receiving assembly, and is characterized in that the light emitting assembly is used for providing a scanning light beam for the detection head; the detection head is used for scanning the surface of the to-be-detected target after receiving the scanning light beam and generating a polar Kerr effect on the surface of the to-be-detected target; and the optical receiving assembly is used for receiving an optical signal fed back by the detection head under the polar Kerr effect and converting the optical signal into stress in the target to be detected. A stress detection method is provided. According to the invention, a light system is constructed by combining the light emitting assembly and the light receiving assembly, so that the detection head can detect the stress in a to-be-detected target by using the polar Kerr effect, the explosion risk is eliminated by using a non-electromagnetic sensing technology, the lift-off effect is overcome by using optical locality measurement, the size of the probe is reduced, and the detection precision is improved. An intrinsically safe and high-precision technical means is provided for rapid stress state scanning in a high-risk environment, and the safety of high-value targets in key industrial fields such as electric power, petrochemical engineering and aerospace is guaranteed.

The invention discloses a high-performance optical comb laser based on heterogeneous material integration and multi-effect fusion, belongs to the technical field of optical communication and laser devices, and aims to solve the problems that a traditional optical comb laser is difficult to start tuning, low in power efficiency, large in line width or limited in bandwidth and the like. A scheme of heterogeneous integration of a III-V group gain material, a low-loss Si3N4 waveguide and a high-electro-optical coefficient barium titanate (BTO) material is adopted, an outer cavity chip comprises a high-Q-value annular resonant cavity, an electro-optical comb is generated by modulating the annular resonant cavity, then a Kerr comb is excited, and the optical comb is amplified through gain. According to the invention, three mechanisms of electro-optical modulation, Kerr effect and semiconductor light amplification are fused, and based on device topological structure innovation and unit device optimization, the problems are solved, the on-chip frequency comb performance is significantly improved, and the optical comb laser with excellent starting and tuning performance, high power, large bandwidth and narrow line width is realized.

A kind of ultra-short pulse synchronization testing device and method based on optical Kerr effect. After the high-power density ultra-short pulse of multiple beams to be synchronized passes through optical Kerr medium, induced birefringence effect occurs, which instantaneously changes the polarization characteristics of the reference light beam, and the synchronization between multiple beams of ultra-short pulses is measured by the amplitude or phase change of the reference signal pulse. This method can realize the synchronization measurement of ultra-short pulses with large angle at the target point, and has the advantages of high measurement accuracy, good repeatability and high stability.

The application discloses a kind of measurement system and method based on magneto-optical Kerr effect, belong to magnetic material measurement and imaging technical field, including three-dimensional displacement platform, optical path unit, electromagnetic unit and software control unit, three-dimensional displacement platform is in the magnetic field provided by electromagnetic unit;Optical path unit includes frame body and the laser generating device, focusing control device, differential signal measuring device and imaging device arranged in frame body interior;Linearly polarized light provided by laser generating device is focused to the sample surface fixed on three-dimensional displacement platform by focusing control device, sample surface reflects and returns focusing control device by reflected light, beam splitting obtains first reflected light and second reflected light, and the focusing control device can move up and down;Differential signal measuring device receives second reflected light to obtain electric signal, and transmit to software control unit;Imaging device receives first reflected light to realize the imaging of sample;Software control unit draws hysteresis loop according to the magnetic field intensity of the magnetic field and electric signal.

The invention provides a high-power femtosecond laser peak power multiplying device based on sheet self-compression. The high-power femtosecond laser peak power multiplying device is composed of a high-power femtosecond laser pulse, a thin lens, a fused quartz solid sheet set, a movable sliding rail, a convex reflector, a dielectric film reflector and a self-compression pulse in sequence in the direction of an incident light beam. The characteristic that negative dispersion can be generated due to the fact that femtosecond laser transmits the fifth-order nonlinear effect in quartz glass is utilized to be balanced with the Kerr effect and the positive dispersion of a quartz glass material, and the spectrum is broadened to achieve pulse self-compression under the condition that the quality of light beams is kept during transmission. Peak power multiplication of high-power femtosecond laser pulses can be achieved in a pulse self-compression mode, and the device has the advantages of being simple in structure, convenient to operate, stable, efficient and wide in application range. The device can be applied to the field of high-power femtosecond laser pulse compression and shaping, and can be better applied to application research of laser electron acceleration, higher harmonic generation and the like.

This invention provides a magnetic detection device based on diamond NV centers and the Kerr effect. It achieves the sharing of light sources and optical paths between magnetic detection technologies based on the magneto-optical Kerr effect and those based on NV centers, combining the two technologies and greatly simplifying the device structure. This increases the intensity of the optical signal received by the detection module, reduces noise interference in the signal, and thus improves the accuracy of magnetic detection. It can simultaneously meet the requirements of rapid and high-resolution detection, and improve the overall detection speed while ensuring detection accuracy.

The invention relates to the technical field of magnetic measuring instruments, in particular to a magneto-optical Kerr effect-based magneton space imaging scanning device and method. The device comprises a transmitting assembly which comprises a laser, a beam expander, a beam splitter, a reflector, a first half-wave plate, a polarization beam splitting cube, a calcite polarizer, a first dichroscope, an objective lens, an LED light transmitting part, a convex lens and an achromatic doublet lens so as to focus an incident beam on an object to be measured; the scanning assembly comprises a second dichroscope, a second half-wave plate, a reflecting mirror, a beam splitter prism, a right-angle reflecting prism, an achromatic doublet lens, a photoelectric balance detector, a lock-in amplifier, a magnetic field applying part and a piezoelectric displacement table and is used for scanning an object to be detected; and the imaging assembly comprises a convex lens, a CMOS camera and a data processing component to generate a morphology image and a spin wave image. According to the invention, high-spatial-resolution, high-magnetic-sensitivity and wide-band spatial imaging measurement can be carried out on the spin wave and the magneton frequency comb.

Provided are: an optical modulation element that exhibits a Kerr rotation angle of at least 0.5°; a spatial light modulator comprising the optical modulation element; and a display device comprising the spatial light modulator. The optical modulation element comprises: a second electrode facing an incident surface on which light is incident; a ferromagnetic ferroelectric layer disposed on the incident surface side of the second electrode; and a ferromagnetic layer disposed on the incident surface side on the ferromagnetic ferroelectric layer. The thickness of the ferromagnetic ferroelectric layer is within the range of 20-100 nm; the thickness of the ferromagnetic layer is within the range of 3-20 nm; and the magnetization of the ferromagnetic ferroelectric layer and the ferromagnetic layer is controlled in accordance with an electrical polarization induced in the ferromagnetic ferroelectric layer by the application of a voltage to the ferromagnetic ferroelectric layer by the second electrode. A part of the incident visible light is transmitted through the ferromagnetic layer and is multiply reflected in the interior of the transparent ferromagnetic ferroelectric layer. The Kerr rotation angle is repeatedly changed in a fixed direction by the Kerr effect with each reflection at the lower surface of the ferromagnetic layer. When the visible light is finally transmitted through the ferromagnetic layer, the visible light exits from the ferromagnetic layer at a giant Kerr rotation angle. The spatial light modulator comprises the optical modulation element. The display device comprises the spatial light modulator.

A laser device (100) is provided with: a seed light source (10) that outputs pulsed light and is capable of controlling the repetition frequency of the pulsed light; an aberration generation unit (20) that applies an aberration caused by an optical Kerr effect to the pulsed light; a beam shaping optical system (30) that adjusts at least one of the beam diameter and the intensity distribution of the pulsed light; a solid-state amplifier (40) that amplifies the pulsed light and emits laser light; and arrangement adjustment units (21, 31) capable of operating at least one of the aberration generation unit (20) and the beam shaping optical system (30) in accordance with the repetition frequency of the pulsed light.

Electrically controllable optical element with a cell (D) filled with Kerr mixture (K) having two substrates (1a, 1b) and a conductive layer (2a, 2b) applied to the inner surface of each substrate (1a, 1b), wherein the Kerr mixture (K) comprises a mixture of rod-shaped molecules with a large dipole moment (5) and semi-mesogens (4) as active components, and wherein the Kerr mixture (K) forms a thin layer with a photopolymerization-produced, wide-mesh, anisotropic network (9) between a structured and / or planar conductive layer (2a, 2b) applied to a substrate (1a, 1b) in a thin-film cell (D), such thatthat, according to the electro-optical Kerr effect, the state of the active composites of semi-mesogens (4) and rod-shaped molecules with a large dipole moment (5) of the Kerr mixture (K) is isotropic without an electric field in the operating temperature range, and a change in the voltage-induced phase shift or refractive index shift in the optical element is generated by electrically continuous adjustment of the voltage U or by applying a constant voltage, characterized in that, in addition to the conductive layer (2a, 2b), an optically effective surface profile (O) is incorporated on the inner surface of a substrate (1a or 1b) or into the substrate (1a or 1b) or of both substrates (1a and 1b).

The application discloses an electromagnetic wave non-reciprocal transmission structure based on light-excited graphene and a transmission method thereof. The structure is composed of silicon rods with different widths placed on a silicon / silicon dioxide substrate, and large-area CVD graphene is transferred to the structure to form a graphene super surface structure. Due to the asymmetry of the structure and the excitation of the nonlinear Kerr effect, the transmission efficiency of electromagnetic waves is significantly related to the incident direction of signal light. By optimizing the structure parameters, the light-excited graphene super surface structure based on the light-excited graphene super surface structure shows a large positive and negative transmission ratio. The device structure is simple and compact, the required incident laser intensity is only 80kW / cm 2 , and is relatively easy to realize in experiments. By utilizing the optical adjustable function of graphene, the working frequency band of the non-reciprocal device can be effectively controlled, thereby flexibly realizing the optical isolation function.

The invention discloses an anti-interference differential polarimeter, which belongs to the technical field of optical measurement instruments, organically combines magneto-optical modulation with a polarization difference method for the first time, solves the problem of weak optical rotation signal detection in an open environment, has a lower glucose solution measurement limit of 0.020 g / mL, has greatly improved anti-interference capability compared with a traditional polarimeter, and has a wide application prospect. For solutions with different concentrations, the average error is maintained at a lower level of 3.25%, not only can light source fluctuation and ambient light interference be overcome and stable measurement be realized, but also subjective judgment of human eyes can be eliminated and objective quantitative reading can be realized. According to the invention, accurate measurement of a glucose solution in a range of 0.020-0.400 g / mL can be realized, automatic data acquisition and real-time concentration display are realized, and the system integrates electromagnetism, optics and information science, can be used as an ideal platform for college physical experiment and common physical experiment teaching, and has a wide application prospect. The method can also be popularized to measurement of physical quantities such as magneto-optical Kerr effect, weak magnetic field and micro displacement, and is wide in application prospect.

The invention discloses a nonlinear lens based on a transformation material and a Kerr effect and a design method, and belongs to the field of optical signal processing and transformation materials. The nonlinear lens is a rectangular lens and is made of a nonlinear material. The spatial refractive index distribution is designed by changing the optical principle, the path instability in a dynamic system is combined with the optical Kerr effect, and the circular lens is adjusted into the square lens with the unstable system path by utilizing the spatial distribution of special material parameters; the weak refractive index change is converted into violent offset of a light beam output position under the instability characteristic of a dynamic system, and under the specific refractive index distribution, the lens has a focusing effect on the light beam propagating in the lens, so that the light beam is enhanced in a local area, and then the nonlinear effect is enhanced; and an optical system with higher speed and lower energy consumption is realized on a simpler device. According to the invention, conformal transformation is adopted, the isotropy of a lens material is ensured, and manufacturing of a nonlinear lens is facilitated.

The application relates to the field of optical technology and discloses a second-order soliton trap transmission state regulation method based on an optical event horizon simulation, which comprises the following steps: preparing a second-order soliton pulse and an external probe pulse, wherein the second-order soliton pulse is generated through the balance of dispersion and nonlinearity in a nonlinear optical fiber, the external probe pulse is a weak power pulse, the group velocity parameter of the second-order soliton pulse and the external probe pulse is measured, and group velocity matching and group velocity mismatch conditions are set; through accurate setting of the group velocity matching and mismatch conditions and quantitative calculation of the refractive index change caused by the soliton pulse based on the Kerr effect, an equivalent event horizon is defined, definite physical parameter benchmarks and stable potential well environments are provided for transmission state regulation, the stability of a soliton potential well action boundary can be determined and ensured, the transmission state misjudgment problem caused by potential well drift and distortion is overcome, and the accuracy of the regulation process and the predictability of the result are ensured.

A method comprises providing an RFOG that includes a resonator in communication with a light source emitting a first signal at a first power level in a CW direction, and a light source emitting a second signal at a second power level in a CCW direction; adding a common intensity modulation to the first signal, to produce an intensity modulated CW signal; adding the same common intensity modulation to the second signal, to produce an intensity modulated CCW signal; introducing the intensity modulated CW signal into the resonator; introducing the intensity modulated CCW signal into the resonator; detecting modulated rate signals that are output from the resonator at a common intensity modulation frequency; and adjusting a power level ratio between the first and second power levels, to determine a modified power level ratio value where a Kerr effect bias instability due to an asymmetrical loss distribution is reduced or eliminated.

The invention discloses a method and system for testing and analyzing magneto-optical parameters of a magnetic multilayer film, and belongs to the technical field of photoelectron data analysis, and the method comprises the following steps: carrying out an ellipsometry test on a to-be-tested magnetic multilayer film sample to obtain ellipsometry parameters of the sample; constructing an optical model according to the structure of the magnetic multilayer film sample to be tested, and performing fitting calculation by combining an optical theory and the ellipsometric parameters obtained by testing to obtain optical property parameters of each layer of film in the sample; the method comprises the following steps: carrying out a magneto-optical ellipsometry test on a to-be-tested magnetic multilayer film sample to obtain a reflection coefficient of the sample in an unmagnetized state and a magneto-reflection coefficient caused by a Kerr effect, deriving a total propagation matrix of light in the magnetic multilayer film sample, and calculating to obtain a Jones matrix of the sample; and calculating the magneto-optical coupling coefficient of each layer of film according to the Jones matrix, the reflection coefficient, the magneto-reflection coefficient and the optical property parameter of each layer of film. According to the invention, accurate characterization of magneto-optical parameters of magnetic multilayer films with various thicknesses, various materials and various layer numbers can be realized.

This application relates to a reconfigurable all-optical nonlinear activation function on a silicon integrated platform. This application provides systems, apparatuses, and methods for an all-optical reconfigurable activation device that implements various activation functions using low input optical power. The disclosed apparatus and system include a directional coupler comprising a first phase-shifting mechanism and an interferometer coupled to the directional coupler. The interferometer includes at least one microring resonator and a second phase-shifting mechanism coupled thereto. The interferometer and directional coupler include a waveguide formed of a first material, while the microring resonator includes a waveguide formed of a second material and a third phase-shifting mechanism. The second material is provided as a low-loss material with a high Kerr effect and a large bandgap to generate various nonlinear activation functions. The first, second, and third phase-shifting mechanisms are configured to control bias within the disclosed system and apparatus to achieve the desired activation function.

This invention relates to the field of semiconductor laser technology, specifically to an on-chip optical pulse neural network computing unit based on thin-film lithium niobate (TFLN) microcavities, comprising: a substrate; a thin-film lithium niobate (TFLN) layer on the substrate; and a microcavity array formed in the TFLN layer. The microcavity array includes at least two cascaded microcavities, arranged linearly or in a two-dimensional grid pattern. Each microcavity supports whispering-gallery modes and has a quality factor, which enhances the intracavity light intensity by approximately Q / (2π) times compared to the input light intensity under critical coupling conditions. In this invention, the second-order electro-optic effect and the third-order Kerr effect of the TFLN achieve Q-value enhancement within the microcavities, enabling on-chip implementation of a nonlinear mapping equivalent to ReLU / Sigmoid, thus overcoming the bottleneck of the lack of intrinsic nonlinearity in silicon-based optical computing.

The invention relates to the technical field of optical fiber mode-locked lasers, and particularly discloses a bending modulation all-optical fiber saturable absorber and a design and preparation method thereof. According to the method, controllable macroscopic bending modulation is introduced into a common single-mode optical fiber, so that linear loss caused by bending is coupled with a nonlinear Kerr effect in the optical fiber. When the incident light power is high, refractive index modulation caused by the Kerr effect enhances the light guide capability of the central area of the optical fiber, so that the original bending loss is partially compensated, and high-intensity light low-loss transmission is realized; and the low-intensity area at the edge of the light field is insufficient in refractive index modulation to compensate for bending loss, so that light energy leakage is enhanced, and low-intensity light high-loss suppression is formed. The light intensity dependent bending loss modulation mechanism constructs the saturable absorption characteristic of an all-fiber, and the saturable absorption behavior can be obtained by using the structure of the fiber. According to the design, the device structure in the mode-locked laser is simplified, the manufacturing cost is reduced, and the compatibility with a polarization maintaining optical fiber system is improved.

The application relates to the technical field of magnetism measuring instruments, in particular to a magnetic sub-space imaging scanning device and method based on the magneto-optical Kerr effect. The device comprises a transmitting assembly, a scanning assembly and an imaging assembly. The transmitting assembly comprises a laser, a beam expander, a beam splitter, a mirror, a first half-wave plate, a polarization beam splitting cube, a calcite polarizer, a first dichroic mirror, an objective lens, an LED light emitting component, a convex lens and an achromatic doublet lens, so as to focus an incident light beam on a to-be-measured object. The scanning assembly comprises a second dichroic mirror, a second half-wave plate, a mirror, a beam splitting prism, a right-angle reflecting prism, an achromatic doublet lens, a photoelectric balance detector, a lock-in amplifier, a magnetic field applying component and a piezoelectric displacement stage, so as to scan the to-be-measured object. The imaging assembly comprises a convex lens, a CMOS camera and a data processing component, so as to generate a topographic image and a spin wave image. The application can perform high spatial resolution, high magnetic sensitivity and wide frequency band spatial imaging measurement on spin waves and magnetic sub-frequency combs.

This invention relates to the field of lenses, specifically to a position-modulable liquid crystal lens based on the principle of electric field superposition. The structure of this invention, from top to bottom, consists of an upper substrate, a liquid crystal layer, a dielectric layer, an electrode layer, and a lower substrate. The liquid crystal layer uses polymer-stabilized blue phase liquid crystal, and the electric field within it is a transverse electric field. According to the Kerr effect and related principles, it can achieve a larger refractive index difference. This invention achieves a transverse electric field in the liquid crystal layer through the principle of electric field superposition; that is, the transverse electric fields between pairs of electrodes are superimposed and enhanced, while the longitudinal electric fields are superimposed and canceled out. This allows for the realization of a transverse electric field in a liquid crystal lens with a single-layer planar electrode architecture, reducing the etching depth of the electrode structure. Furthermore, this invention modulates the sinusoidal driving voltage applied to the electrodes, achieving a transverse shift in the lens's refractive index distribution. The minimum precision of this transverse shift is the distance between two adjacent electrodes, thus enabling precise adjustment of the liquid crystal lens's position.

The invention discloses a method for measuring the oil gap insulation characteristic of an on-load tap-changer under high frequency, and belongs to the technical field of electrical equipment monitoring and fault diagnosis. Comprising the following steps: arranging an on-load tap-changer between a high-voltage winding and a neutral point or between a network side winding and the neutral point; building an ultrahigh frequency monitoring system, and carrying out on-load tap-changer switching discharge monitoring and contact gap insulating oil partial discharge monitoring; a partial discharge detector is used for carrying out partial discharge monitoring on insulation oil degradation of the on-load tap-changer; and two-dimensional electric field measurement is carried out through a Kerr effect method. The on-load tap-changer main contact switching discharge process is monitored, the time domain waveform is obtained, and an effective monitoring means is provided for analyzing the discharge phenomenon in the switching process.

The invention discloses a Kerr effect error-based splitting ratio on-line test system and an on-line test method for a multifunctional phase modulator of an interference type fiber-optic gyroscope. The online test system comprises a light source, a light intensity modulator and a fiber-optic gyroscope, a first port of an input side of the light intensity modulator is connected with the light source, a first port of an output side of the light intensity modulator is connected with the fiber-optic gyroscope, a second port of the input side of the light intensity modulator and a second port of the output side of the light intensity modulator are both in a suspended state, and the fiber-optic gyroscope is connected with the light source. The light intensity modulator is used for modulating the intensity of the light signal emitted by the light source so as to generate the light signal intensity used for the splitting ratio test. The on-line testing system is simple in structure and easy to implement, has high real-time performance and reliability, can be effectively used for performance monitoring and calibration of the MIOC in system operation, and provides a feasible technical approach for improving the stability and precision of the interference type fiber-optic gyroscope.

This disclosure provides an on-chip silicon-based electro-optic modulator comprising: an input waveguide; a Mach-Zehnder type modulation unit, the input end of which is connected to the input waveguide, the Mach-Zehnder type modulation unit including a modulation arm, the arm length of which is less than 2 mm to increase the bandwidth of the output optical signal; a nonlinear switching unit including: a first 1×2 beam splitter connected to the output end of the Mach-Zehnder type modulation unit; a first power arm connected to one output end of the first 1×2 beam splitter; a second power arm connected to the other output end of the first 1×2 beam splitter, the power of the second power arm being higher than that of the first power arm; and a 2×2 coupler including a first output port and a second output port, the two input ends of the 2×2 coupler being connected to the first power arm and the second power arm respectively, the 2×2 coupler being configured to respond to an increase in the phase difference due to the Kerr effect, thereby increasing the extinction ratio of the modulation signal output from the first output port.

Disclosed is a method for reducing the Kerr effect in an interferometry measuring device including a generator configured to emit an input periodic light signal, and a Sagnac interferometer in which two counterpropagating signals travel and combine so as to form a periodic output signal having at least two power values, the method including: determining a phase shift between the two counterpropagating signals a first time, and cancelling out the phase shift; and then determining a phase shift between the two counterpropagating signals a second time; and adjusting the ratio between the average powers of the counterpropagating signals so as to cancel out the value of the phase shift determined in the second determination. Also disclosed is an interferometry measuring device configured to implement such method.

Structures including a grating coupler and a layer that exhibits an electric-field-induced Pockels effect and methods of forming such structures. The structure comprises a first grating coupler on a substrate, a second grating coupler having an overlapping relationship with the first grating coupler, and a layer including a portion having an overlapping relationship with the second grating coupler. The layer comprises a material that exhibits an electric-field-induced Pockels effect.

The application discloses a method for forming a magnetic skyrmion based on femtosecond laser pulse regulation and a writing device, and the method comprises the following steps: obtaining a CoFeB nanodisk and placing the CoFeB nanodisk in a sample placement area of a magneto-optical Kerr effect microscope; performing pulse excitation on the CoFeB nanodisk by adjusting a femtosecond laser thermal pulse, controlling the generation and annihilation of skyrmions of the CoFeB nanodisk in a preset area, and obtaining the number and position of the skyrmions; and performing data writing and reading according to the generation and annihilation of the skyrmions and the number and position of the skyrmions. The device comprises a femtosecond laser pulser, a CoFeB nanodisk and a temperature sensor. The embodiment of the application can reduce energy consumption, avoid the interference of external noise, and further improve the accurate control ability of the number and position of the skyrmions. The application can be widely applied in the technical field of spin electronics.

Electrically controllable optical element with a Kerr cell filled with Kerr fluid, comprising two substrates (1) and a conductive layer (2) applied to the inner surface of the substrate (1), characterized in that the Kerr fluid (K) has a mixture of rod-shaped (5) and non-rod-shaped (4) molecules as active composites and that the Kerr fluid (K) forms a thin layer with a preformable, open-mesh, anisotropic network (9) between the structured and / or planar conductive layers (2) applied to the substrates (1), such that the state of the active composites (4, ) is determined according to the electro-optical Kerr effect.5) the Kerr fluid (K) is isotropic without an electric field in the operating temperature range (RT) and a change in the voltage-induced phase shift or refractive index shift of the optical element is produced by electrically continuous adjustment of the voltage (U) or by switching the voltage (U) on / off.

A kind of test system, method and magneto-optical kerr effect criterion method of high-order magneto-optical kerr effect in ferromagnetic film belong to the field of spintronics and magneto-optics. By building a magneto-optical kerr detection light path, the direction of the external magnetic field is regulated by the quadrupole magnet to regulate the magnetic moment direction of the sample, and the light intensity change curve under the rotating magnetic field is detected by the photodetector. Whether the sample has second-order magneto-optical kerr effect (QMOKE) is characterized, and the intensity is quantitatively observed. The method only needs a single light intensity change curve obtained by vertical incidence as the characterization basis of QMOKE, and the measurement method of small step (5°) rotation of external magnetic field comprehensively characterizes the influence of magnetic field direction on QMOKE signal, and can calculate QMOKE intensity according to amplitude, simplifies the steps of separating first-order magneto-optical kerr effect (LMOKE) and QMOKE, and simplifies the characterization criterion of QMOKE effect of ferromagnetic film system, especially Fe structure film.