37 results about "Elliptically polarized light" patented technology

The invention relates to the technical field of optical element surface shape dynamic measurement scheme design, in particular to an element surface shape dynamic measurement system based on a metasurface. According to the scheme, polarized light emitted by a laser is split into reference light and test light, the test light passes through a quarter-wave plate twice to realize polarization orthogonalization, and the test light is combined with the reference light to form elliptically polarized light; synchronously capturing component intensities of left-handed / right-handed circular polarized light and orthogonal line polarized light by using a detector, and resolving a phase difference delta in real time by combining a Stokes parameter; environmental interference is eliminated based on a common-path design, a polarization beam-splitting element is omitted, and the architecture is simplified; accurate dynamic measurement of the surface shape of the measured piece is realized by deducting the inherent surface shape error of the system. The system provided by the invention has the advantages of strong anti-interference performance, high measurement efficiency, remarkable cost reduction and the like, and is suitable for precise optical manufacturing and on-line detection scenes.

The present invention provides a distance calculation device that can calculate distance information relating to the distance a workpiece travels. [Solution] The system comprises a light source 10 that emits light, a first optical system 20 that converts the light from the light source into elliptical polarization and emits it toward a workpiece W1 that is transparent and moving in a specific direction, a second optical system 30 that converts the light from the workpiece into linear polarization and emits it, and an optical sensor 40 that acquires optical information of the workpiece based on the light from the second optical system. The first optical system includes a first polarizing filter 22 that converts to linear polarization and a first waveplate 23 that converts the linear polarization from the first polarizing filter into elliptical polarization. The second optical system 30 includes a second waveplate 31 that converts the light from the workpiece and a second polarizing filter 32 that is placed between the second waveplate and the optical sensor 40 and converts the light from the second waveplate into linear polarization.

A stereoscopic display device (100) includes a first image display section (110) that outputs first image light (151) of linearly polarized light, a second image display section (120) that outputs second image light (152) of linearly polarized light, a first phase difference plate (112) that modulates the first image light (151) output from the first image display section (110) to convert it into first elliptically polarized light, a second phase difference plate (122) that modulates the second image light (152) output from the second image display section (120) to convert it into second elliptically polarized light that rotates in the same direction as the first elliptically polarized light, and a half mirror (130) that transmits the first elliptically polarized light to make it first circularly polarized light that rotates in the same direction as the first elliptically polarized light, and reflects the second elliptically polarized light to make it second circularly polarized light that rotates in the opposite direction to the second elliptically polarized light.

A three-dimensional display device includes: a first image display that outputs linearly polarized first image light; a second image display that outputs linearly polarized second image light; a first retardation plate that modulates and converts the first image light output from the first image display to first elliptically polarized light; a second retardation plate that modulates and converts the second image light output from the second image display to second elliptically polarized light that rotates in a direction identical to a rotation direction of the first elliptically polarized light; and a half mirror that transmits the first elliptically polarized light, converts the first elliptically polarized light to first circularly polarized light that rotates in a direction identical to the rotation direction of the first elliptically polarized light, reflects the second elliptically polarized light, and converts the second elliptically polarized light to second circularly polarized light that rotates in a direction opposite the rotation direction of the second elliptically polarized light.

The invention relates to an assembly error elimination method for a liquid crystal polarization state controller, which comprises the following steps of: constructing an assembly error model by adopting a Mueller matrix, and simulating and analyzing an influence rule of an angle error of a polaroid and an LCVR2 (Liquid Crystal Voltage Receptor 2) on a polarization state; based on an influence rule of assembly errors, a two-step correction strategy based on computer-aided assembly and adjustment is provided. The two-step correction strategy comprises the following steps: firstly, carrying out angle correction on a polaroid by taking ellipsometric skewness of circularly polarized light as a criterion; then, angle correction of the LCVR2 is carried out on the basis of the included angles among the three pieces of linearly polarized light; an experiment light path is built for experiment verification, and meanwhile, the installed and adjusted liquid crystal polarization state controller is used for generating elliptically polarized light to verify the effectiveness of installation and adjustment. The method can effectively eliminate the assembly error, and achieves the high-precision output of the polarization state.

The invention discloses a polarization selection detection system and method for laser frequency locking and coherent population trapping resonance, and relates to the field of optoelectronics. Linear polarized light emitted by the vertical cavity surface emitting laser is changed into elliptically polarized light through the first lambda / 4 wave plate and then acts with 87Rb atoms in the atomic bubble, polarization selection is achieved by adjusting the included angle between the optical axes of the first lambda / 4 wave plate and the second lambda / 4 wave plate, and a light beam completing polarization selection is divided into two beams through the second lambda / 4 wave plate, the lambda / 2 wave plate and the polarization beam splitter. And the first photoelectric detector and the second photoelectric detector are respectively used for detection to obtain photoelectric signals. According to the invention, laser frequency locking can be realized at the same time, background signals brought by VCSEL fundamental frequency and high-order sideband light in CPT signals are removed, and the signal contrast is improved.

Provided is a lens device, an optical filter unit, and an imaging device that can suppress the generation of ghost images. The lens device includes an optical filter unit in an optical path. The optical filter unit includes a plurality of openings including a first opening and a second opening, at least the first opening and the second opening include a band-pass filter, and at least one of an object side and an image side of the band-pass filter includes an optical element. The optical element includes a polarizing filter and a wave plate that converts linearly polarized light into circularly polarized light or elliptically polarized light, and the first opening and the second opening pass light of mutually different wavelength regions and polarization directions.

The utility model provides a focal plane full polarization sensing device, including substrate, phase delay layer, polarization detection layer and CCD sensor, the phase delay layer and polarization detection layer are arranged on one side of substrate in proper order, the phase delay layer has a plurality of phase delay zone in array arrangement, and the CCD sensor is arranged in the phase delay zone. The phase delay area comprises 2x < 2 > pixel units in different fast axis directions, the polarization detection layer is in single horizontal orientation, and the phase delay layer and the polarization detection layer are combined to form an elliptical polarization array, so that the simultaneous detection of four elliptical polarized lights is realized. The manufacturing process of the focal plane splitting polarization sensing device based on the metal wire grating is simplified, the manufacturing cost is reduced, efficient polarization imaging of the infrared band can be achieved, and the multi-band compatibility of the device is improved.

The invention provides a light generating system (1000) comprising a first light generating device (110), a luminescent material (200), a diffuser assembly (700), optical elements (500), and a light exit (1090), wherein; (A) the first light generating device (110) is configured to generate first device light (111); (B) the optical elements (500) comprise a first redirection optical element (1510) configured in a light-receiving relationship with the first light generating device (110); wherein the first redirection optical element (1510) is configured to (i) direct the first device light (111) in an optical path to the diffuser assembly (700), and to (ii) direct at least part of diffused device light (711) in an optical path to the luminescent material (200) (C) the diffuser assembly (700) comprises (a) a diffuser (710), wherein the diffuser (710) comprises a polarization maintaining diffuser, wherein the diffuser (710) is configured in the reflective mode; wherein the diffuser (710) is configured to diffuse at least part of the first device light (111) received by the diffuser (710) into diffused device light (711), wherein the diffused device light (711) has a full width half maximum of at least 5°; and (b) a quarter waveplate (720); wherein the light generating system (1000) is configured such that first device light (111) reaching the quarter waveplate (720) comprises linearly polarized light; wherein the quarter waveplate (720) is configured to convert linear polarized light received by the quarter waveplate (720) into elliptical polarized light and to convert elliptical polarized light received by the quarter waveplate (720) into linear polarized light; wherein the diffuser assembly (700) is configured to provide the diffused device light (711) in an optical path to the luminescent material (200) via the first redirection optical element (1510); (D) the luminescent material (200) is configured to convert at least part of the diffused device light (711) received by the luminescent material (200) into luminescent material light (201); (E) the optical elements (500) are configured to direct at least part of the luminescent material light (201) in an optical path to the light exit (1090); and (F) the light generating system (1000) is configured to generate in an operational mode of the light generating system (1000) system light (1001) comprising at least part of the luminescent material light (201).

The invention relates to dynamic adjustable optical tweezers based on a polarization-sensitive transverse bifocal superlens, and belongs to the field of optical tweezers technology and micro-nano optics. According to the super-lens, dynamic regulation and control of a focus are realized by using sensitive response of the silicon nano-column array to polarization through a composite propagation phase and a geometric phase. Under linear polarization or elliptically polarized light, the system can generate transversely symmetrical double focuses; under the circularly polarized light, a single-side focus is formed. By adjusting the polarization state of incident light, a double-particle capture mode, a single-particle capture mode and a particle transverse transport mode can be flexibly switched. According to the invention, the physical structure does not need to be changed, the dynamic control can be realized only by external optical regulation and control, the structure is compact, the integration degree is high, the control is flexible and the like, and a new technical approach is provided for an on-chip particle control system.

A single-optical-path atom magnetometer based on a left-handed and right-handed circularly polarized light beam splitting metasurface belongs to the field of quantum precision measurement, and is characterized in that a laser corresponding to an alkali metal excitation wavelength emits a light beam, elliptically polarized light is emitted through a linear polarizer and a quarter-wave plate, and then enters a glass gas chamber containing alkali metal gas, and under the action of an external magnetic field, the elliptically polarized light is emitted to the left-handed and right-handed circularly polarized light beam splitting metasurface; incident elliptically polarized light generates an optical rotation angle, emergent light enters the left-handed and right-handed circularly polarized light beam splitting metasurface after being subjected to polarization conversion of the quarter-wave plate, left-handed and right-handed circularly polarized components of the incident light are subjected to beam splitting and respectively enter the corresponding photoelectric detectors, and precise measurement of an external magnetic field is realized through calculation processing of a rear-end circuit. The method has the advantages that under the condition that the single-optical-path compact structure of the atom magnetometer is reserved, elliptically polarized light is adopted as incident light, and high-sensitivity magnetic field measurement based on the rotation angle detection method is achieved through the left-handed and right-handed circularly polarized light beam splitting metasurfaces.

A light filter including first and second optical elements having light-absorbing transition dipole moments orientated with a tolerance of at most 20° parallel to a first direction for the first optical element and for the second optical element parallel to a second direction so light incident in the first or second optical element is transmitted or partially absorbed, depending on its direction of incidence relative to the respective element and its polarization state. A delay layer is between the elements as a C- or A-plate so that at least 85% of linearly- or elliptically-polarized light incident into the light filter at an angle of at least 35° to the first or second direction is absorbed, wherein the angle between the electric field of the linearly-polarized light or long half-axis of the elliptically-polarized light and the direction of incidence, projected onto the surface of the light filter, is less than 20°.

The embodiment of the invention relates to the technical field of display, and provides a phase adjusting element, a display module and electronic equipment. The phase adjustment element includes a light transmissive substrate, a light transmissive coating on a surface of the substrate, and a liquid crystal polymer layer on a surface of the coating away from the substrate. The refractive index of the liquid crystal polymer layer is larger than that of the coating, and the thickness of the liquid crystal polymer layer is variable, so that linearly polarized light entering the phase adjusting element from one side of the substrate is converted into mixed polarized light to be emitted after passing through the liquid crystal polymer layer, and the mixed polarized light contains linearly polarized light, circularly polarized light and elliptically polarized light. When the phase adjusting element is applied to the display module, the visual fatigue of a viewer is reduced, the brightness of the display module is improved, and the power consumption of the display module is reduced.

An identification medium including a light reflection layer and a patterned phase difference layer, wherein the light reflection layer is a layer that reflects incident light as circularly polarized light or linearly polarized light, and the patterned phase difference layer is a layer that includes an area having a phase difference, and is a layer provided in the identification medium so that the area having a phase difference occupies a partial area of a display surface of the identification medium. Also provided are an article including the identification medium, and a method for using the identification medium wherein, in observation of the reflected light, a linear polarization component or a circular polarization component of the reflected light is selectively observed, or linearly polarized light, circularly polarized light, or elliptically polarized light is made incident as the incident light.

The application discloses an ellipsoidal light magnetic signal detection system and method based on a cascade super surface, wherein the system utilizes a cascade super surface polarization conversion device to emit elliptical polarized light with specific ellipticity, and guides the elliptical polarized light into an atomic chamber to interact with alkali metal atoms to realize magnetic field measurement. According to the required ellipticity, the application designs the Jones matrix of the cascade super surface, designs the material, structure and period of the super surface, converts the light emitted by a laser into elliptical polarized light with a predetermined ellipticity, and after the elliptical polarized light enters the atomic chamber, the optical rotation effect is generated while the alkali metal atoms are polarized, and the differential detection technology and the lock-in amplification technology are utilized to obtain the magnetic field information to be measured. Compared with a conventional magnetic signal detection system, the magnetic signal detection system built by using the cascade super surface polarization conversion device has the advantages of small volume and easy integration due to the compact structure and the miniaturized design concept.

An optical fiber current sensing controller module, where an optical transmitter is energized from a DC source and emits an optical field of calibrated intensity and wavelength to a linear polarizer which generates a reference signal which is then launched in alignment with the transmission axes of a polarization maintaining optical fiber link to a remote and passive fiber optic current sensor (FOCS), where the linearly polarized optical pulse traverses a complete circular path around an energized conductor and is subject to polarization plane rotation in proportion to the magnetic flux density with the integration equal to electric current magnitude according to Ampere's law, and the rotated polarized optical pulse is transmitted back to the optical fiber current sensing controller module via a return fiber optic cable, where the Stokes vector polarization parameters for the returned optical signal are calculated by splitting the elliptically polarized field into four components, passing these components through an analyzer comprised of a linear horizontal polarizer, a linear vertical polarizer, a linear polarizer with transmission axis set at 45 degrees, and a linear polarizer with transmission axis set at 135 degrees, respectively, and where the four separate outputs of the four fiber optic polarizing filters are connected respectively to four separate photodiodes which transduce each optical intensity to analog voltage outputs which are sampled by a digital signal processing chipset, where the Stokes vector parameters for the polarized optical signal are calculated directly from the digitally sampled array of optical intensity values transduced by the photodiodes, and the change in polarization state from which electrical current is measured is derived by comparing the initial linear polarization Stokes vector of the generated reference signal with the measured Stokes parameters of the elliptically polarized optical signal received from the analyzer, and where a sample of the generated polarized reference signal is measured at a photodiode to monitor online sensor network optical attenuation and reference signal power fluctuations.

The invention belongs to the technical field of rotational motion, and relates to a remote speed measurement method and system based on a partially coherent rotational Doppler Effect. Gaussian-Schell model partially coherent light is modulated into a circular polarization state and then is irradiated to a rotating object to be measured, and elliptically polarized light reflected by the rotating object to be measured is modulated by using a rotating linear polarizer; generating a first periodic time-domain light beam related to polarization information, screening the first periodic time-domain light beam by using a post-modulation mask of a three-hole structure to obtain a second periodic time-domain light beam related to rotation speed information, and performing Fourier transform on the second periodic time-domain light beam to obtain a Fourier spectrum; acquiring a polarization peak signal and a rotation peak signal in the Fourier spectrum, calculating the angular velocity of the rotating object to be measured based on the frequency of the rotation peak signal, and obtaining the polarization response of the rotating object to be measured based on the amplitude of the polarization peak signal and the amplitude of the rotation peak signal. According to the scheme, the rotating speed of an off-axis object can be accurately measured, and polarization response characteristics are obtained.

This invention relates to the field of optical engineering technology, specifically disclosing a polarized optical lens glare elimination system for vehicle-mounted security. The system includes: a reference polarization module, which constructs a controllable environment simulation test platform to collect reflected light data under different incident angles and water film thicknesses, calculates the degree of polarization and phase difference using the Stokes vector method, and constructs a quasi-polarized light characteristic library; a composite filtering module, which collects real-time reflected light data and compares it with the quasi-polarized light characteristic library to determine elliptically polarized light, and corrects it to linearly polarized light through phase compensation; a direction calibration module, which calculates the optical path deviation angle through a real-time direction calibration module and dynamically adjusts the filtering direction; a glare recognition module, which performs light intensity analysis on the corrected light to determine glare residue, identifies micro-glare spot areas through polarization degree calculation; and a grayscale correction module, which extracts the average grayscale value of the normal area and corrects the grayscale of the spot pixels, thereby achieving dynamic elimination of glare from reflected light on wet road surfaces.

The invention relates to a liquid crystal composition, an optical film, a polaroid and a display device, the liquid crystal composition is applied to a random depolarization functional layer, and the liquid crystal composition comprises a polymerizable liquid crystal material, the polymerizable liquid crystal material comprises at least one first liquid crystal compound as shown in a formula I and / or at least one second liquid crystal compound as shown in a formula II. The liquid crystal composition provided by the invention can be used for manufacturing a random depolarization functional layer, so that linearly polarized light is randomly converted into circularly polarized light and / or elliptically polarized light; therefore, the display device applying the random depolarization function layer realizes healthy eye-protection display.

The invention relates to the technical field of inter-satellite laser communication. The invention discloses an inter-satellite laser communication adaptive dynamic light splitting device and method, a satellite and a system, which can realize dynamic adjustment of a tracking light path and a communication light path splitting ratio, and is high in response speed and simple in structure. The device comprises a micro-electro-mechanical system and a polarization beam splitter, and the micro-electro-mechanical system is used for adjusting the phase delay amount of linearly polarized light at the current moment according to an adjusting signal and then outputting elliptically polarized light; and the polarization beam splitter is used for carrying out polarization state separation processing on the elliptically polarized light to obtain a first polarized light beam and a second polarized light beam corresponding to the current moment.

This invention provides a single-optical magnetic signal detection system and method based on a polarizing body grating, comprising: a laser, a pre-optical path unit, an atomic gas cell unit, a polarization detection unit, and a signal processing unit. The light emitted by the laser is modulated into elliptically polarized light by the pre-optical path unit and acts on the atomic gas cell unit, causing the alkali metal atoms to spin polarize. The polarization detection unit and signal processing unit then measure the magnitude of the external magnetic field using optical rotation detection. This method combines the advantages of existing single-optical and dual-optical atomic magnetometers, featuring a compact structure and simplified optical path. Differential detection suppresses common-mode noise, improving measurement accuracy and sensitivity. The optically pumped atomic magnetic resonance polarization detection is achieved using a liquid crystal polarizing body grating thin-film device with efficient polarization chiral splitting and large-angle single-order diffraction performance, realizing miniaturized design of the magnetic measurement system and laying the foundation for the system to move towards chip-level design.

A laser oscillator, comprising: a resonant cavity; a light source module (30), provided in the resonant cavity, the light source module (30) being configured to be able to output a first light beam, and the first light beam comprising elliptically polarized light; and a quarter-wave plate (40), provided in the resonant cavity and arranged on one side of the light source module (30) in the optical axis direction of the light source module (30), the quarter-wave plate (40) being perpendicular to the optical axis, and the quarter-wave plate (40) being configured to convert the elliptically polarized light in the first light beam into polarized light of a target type, so as to form a second light beam. The laser oscillator can achieve high-power pumping of a gain medium without being limited by the physicochemical properties of crystals, does not need selection of special crystal orientations of isotropic crystals, and improves the laser output efficiency.

The present application relates to an optical film, a polarizer, and a display device. The optical film includes a substrate layer and a depolarization layer located on one side of the substrate layer. The depolarization layer includes at least one main layer and birefringent particles dispersed in the at least one main layer. The angle between the slow axis direction of the birefringent particles and the winding direction of the substrate layer is greater than or equal to 35° and less than or equal to 55°. When linearly polarized light is incident on the optical film, the linearly polarized light is converted into circularly polarized light and / or elliptically polarized light by the depolarization layer. The present application can achieve a depolarization effect through a method with a simpler process, lower cost, and higher yield, thereby providing eye protection.

Provided are a lens device, a filter unit, and an imaging apparatus capable of suppressing occurrence of ghosts. The lens device includes a filter unit in an optical path. The filter unit has a plurality of opening portions including a first opening portion and a second opening portion. At least the first opening portion and the second opening portion each include a band-pass filter, and each include an optical element on at least one of an object side or an image side of the band-pass filter. The optical element is composed of a polarized light filter and a wave plate which converts linearly polarized light into circularly polarized light or elliptically polarized light. The first opening portion and the second opening portion pass light in different wavelength regions and different polarization directions.

The invention relates to a liquid crystal composition, an optical film and a display device. The first liquid crystal material comprises at least one compound represented by the following structural formula; the second liquid crystal material comprises one or a combination of more of the compounds; the optical film prepared from the liquid crystal composition provided by the invention shows excellent optical performance, not only has high transmittance, but also can randomly convert linearly polarized light into circularly polarized light or elliptically polarized light, realizes conversion from the linearly polarized light to natural-like light, synchronously keeps relatively small color cast, and has a wide application prospect. The eye protection effect is achieved, and meanwhile the influence on the display effect is small.

The invention provides a light generating system comprising a first light generating device, a second light generating device, a diffuser element, a polarization changing element and a first polarization beam splitter wherein: (A) the first light generating device is configured to generate first device light having a first peak wavelength ([lambda] p1); wherein the second light generating device is configured to generate second device light having a second peak wavelength ([lambda] p2); wherein lambdap2-lambdap1 > = 10 nm; wherein the first light generating device and the second light generating device each comprise a diode laser or a super light emitting diode; (B) the light generating system is configured such that: (a) both the first device light and the second device light reaching the first polarizing beam splitter comprise a first type of linearly polarized light; (b) the first device light and the second device light propagate in a manner that: (i) at least a portion of the first device light and the second device light are reflected or transmitted at the first polarization beam splitter, depending on the type of linear polarization, via the first polarization beam splitter; the first device light (iii) passes through a polarization altering element configured to convert linearly polarized light into elliptically polarized light (iii) to a diffuser element at which at least a portion of the first device light and at least a portion of the second device light are diffused into diffused first device light and diffused second device light, respectively, meanwhile, the direction of the elliptically polarized light is changed into an opposite direction; (c) at least a portion of the diffused first device light and at least a portion of the diffused second device light propagate in such a manner that (i) through a polarization changing element at which at least a portion of the elliptically polarized light is converted into a second type of linearly polarized light different from the first type of linearly polarized light, to (ii) a first polarizing beam splitter at which at least a portion of the diffused first device light and at least a portion of the diffused second device light are transmitted or reflected depending on the type of linear polarization; and (C) the polarization changing element comprises a [lambda] / 4 wave plate configured to be an (n / k1) [lambda] / 4 wave plate for a first peak wavelength ([lambda] p1) and an (m / k2) [lambda] / 4 wave plate for a second peak wavelength ([lambda] p2), where n and m are odd positive integers, n-m is an even positive integer, and where k1 and k2 are each independently selected from the range of 0.8-1.2.

The invention discloses an optical film, an optical film material and a display device, the optical film comprises a base material layer and a depolarization function layer arranged on one side of the base material layer, the depolarization function layer comprises N liquid crystal film layers, the N liquid crystal film layers are stacked in the thickness direction of the optical film, and N is larger than or equal to 2; wherein the alignment directions of any two liquid crystal film layers are different, and the optical film is configured to convert linearly polarized light incident to the optical film into elliptically polarized light and / or circularly polarized light with randomly distributed light vectors; the optical film can convert linearly polarized light into elliptically polarized light or circularly polarized light similar to natural light so as to achieve the effect of eye protection.

The invention belongs to the technical field of ocean polarized light detection, and discloses a light source unit with polarization mode distribution characteristics, a device and a control method. The light source device is formed by arranging a plurality of light source units vertically and horizontally, incident monochromatic light is divided into three paths by a beam splitter, and the first path of light is a linearly polarized light control light path and is processed by a linearly polarized light control unit; the second path of light is an elliptical polarized light control light path and is processed by an elliptical polarized light control unit; and the third path of light is a bypass light path of the incident light. The linearly polarized light control unit is formed by connecting a linearly polarized light intensity control subunit and a linear polarization angle adjusting subunit in series, and the elliptically polarized light control unit is formed by connecting an elliptically polarized light intensity control subunit and an elliptically polarized mode adjusting subunit in series. Based on the light source device, four polarization distribution images generated by a computer can be utilized to control polarization parameters such as a polarization angle, a polarization degree and a polarization mode of light emitted by each light source unit, so that an area light source with expected polarization mode distribution characteristics is realized.

Embodiments of the present disclosure are directed to a display panel and a display device. The display panel includes a light-emitting functional layer disposed on a substrate, a dimming metal array layer disposed on a side of the light-emitting functional layer away from the substrate, and a circular polarizer. The circular polarizer includes a linear polarizing layer and a quarter-wave plate disposed on a side of the dimming metal array layer away from the light-emitting functional layer. The dimming metal array layer is configured to convert light into elliptically polarized light. A included angle between an elliptical long axis direction of the elliptically polarized light and a light transmission axis direction of the linear polarizing layer is less than or equal to 45 degrees.

The embodiment of the invention discloses an active Q-switched laser device. The device comprises a pumping source used for emitting pumping light and enabling the pumping light to enter an Nd: YVO4 crystal; the Nd: YVO4 crystal comprises a first end face and a second end face, the first end face is perpendicular to the incident direction of the pump light, a wedge angle is formed between the first end face and the second end face, and the Nd: YVO4 crystal is used for separating the laser into first polarized light and second polarized light and enabling the first polarized light to be emitted from the second end face at a first refraction angle; the electro-optical Q switch unit receives vertically incident first polarized light, forms an equivalent quarter-wave plate according to a control signal and vertically outputs elliptically polarized light; the quarter-wave plate receives vertically input elliptically polarized light and vertically outputs third polarized light; and a part of the transmission film receives the vertically incident third polarized light, vertically reflects a part of the third polarized light into the resonant cavity for active Q-switching, and vertically outputs the other part of the third polarized light and the laser subjected to active Q-switching.