113 results about "Double crystal" patented technology

The invention discloses a laser frequency stabilization system based on Faraday anomalous dispersion atomic filtering, which is used for carrying out frequency stabilization on phase modulation multi-sideband laser, and comprises a frequency doubling laser unit which is configured to comprise a fundamental frequency seed light source, an electro-optical modulator, a fundamental frequency amplifier and a frequency doubling crystal; the light splitting module unit is configured to split the frequency doubling light into a main output light path and a monitoring light path; the atomic optical rotation filter is located on the monitoring light path and is configured to maintain the purity of the frequency-stabilized laser spectrum through purification treatment under the control of the axial magnetic field and the temperature; the frequency stabilization unit is configured to be a frequency stabilization light path and a servo system, and the frequency stabilization light path is used for obtaining laser frequency information and generating an error signal; the servo system is used for controlling the frequency of the fundamental frequency seed light source according to the error signal feedback. According to the laser frequency stabilization system provided by the invention, the spectrum purification and frequency stabilization precision can be improved, so that high-frequency stability locking is realized.

The invention provides a temperature compensation method and device for laser frequency doubling, electronic equipment and a storage medium. The method comprises the steps that the initial temperature of a frequency doubling crystal of a frequency doubling laser is determined according to the power of input fundamental frequency light; adjusting the initial temperature, and determining a target temperature corresponding to the maximum value of the frequency-doubled optical power output by the frequency-doubled laser; according to the invention, active following compensation is carried out on the temperature of the frequency doubling crystal, and the temperature of the frequency doubling crystal is controlled at the target temperature, so that the active following compensation is carried out on the temperature of the frequency doubling crystal, thereby enabling the frequency doubling laser to maintain high output power, and further improving the frequency doubling efficiency of the crystal. Therefore, the laser frequency multiplier can quickly reach a steady state in the power switching process, and accurate dynamic control of the laser frequency multiplication system is realized.

The invention discloses a miniature integrated infrared gas sensor chip, which belongs to the technical field of sensors, and comprises a first wafer and a second wafer, and the first wafer and the second wafer are connected in a combination manner and form an optical gas chamber; a vent hole is formed above the first wafer, and a reflective film layer is plated on the inner wall of the optical gas chamber and is arranged to only allow infrared light emitted by the infrared light source to pass through; a periodic micro-nano structure is arranged in the optical gas chamber; the surface of the second wafer is covered with an insulating film layer, and an infrared light source and an infrared detector are arranged above the insulating film layer. An optical gas chamber is formed through double-wafer bonding, a periodic micro-nano structure is integrated to enhance interaction between infrared light and gas, environmental interference is suppressed in combination with a double-channel differential detector, and meanwhile stability and selectivity are improved through multi-layer structures such as a reflective film layer, a protective film layer and a composite insulating film layer. And finally, a miniaturized and high-sensitivity gas detection function is realized.

The invention discloses a bamboo-based large-interlayer-spacing homogeneous graphite-like sub-crystal carbon material and a preparation method and application thereof, the bamboo-based large-interlayer-spacing homogeneous graphite-like sub-crystal carbon material comprises a homogeneous graphite-like sub-crystal carbon material, and the homogeneous graphite-like sub-crystal carbon material is characterized by being composed of 3.714.0 large-interlayer-spacing approximately-parallel oriented carbon sheets. When the homogeneous graphite-like subcrystal carbon material is used for a sodium ion battery negative electrode, the initial coulombic efficiency reaches 94.4%, the initial charging specific capacity reaches 353.5 mAh / g, and the performance is comparable with that of a lithium battery graphite negative electrode. The preparation method comprises the following steps: by taking bamboo wood as a precursor, fully inducing a macroscopic bamboo wood continuum to generate an oxygen-containing six-membered ring network intermediate product by taking a graphite container and graphite powder as double seed crystals at low temperature; and inducing an intermediate product with a proper particle size at a high temperature by taking a graphite container as a single crystal seed to prepare the graphite-like subcrystal carbon material with a uniform structure. The method takes a bamboo source as a raw material, is simple in process and low in energy consumption, and has remarkable industrialization potential.

The invention relates to the technical field of all-solid-state lasers, and particularly provides a master-slave pulse delay controllable ultraviolet dual-wavelength double-pulse laser, which comprises a pumping source and a V-shaped folded resonant cavity, and is characterized in that the V-shaped folded resonant cavity comprises an input mirror, a gain medium, a Q-switched crystal, a total reflective mirror, a frequency doubling crystal and an output mirror; wherein the Q-switched crystal performs step-type modulation through a double-step electric signal, the double-step electric signal sequentially comprises a high-voltage stage, a low-voltage stage and a voltage-reducing stage in a modulation period, and the double-step electric signal sequentially generates jump from the high-voltage stage to the low-voltage stage and jump from the low-voltage stage to the voltage-reducing stage in a pumping period. The dual-wavelength master pulse and the dual-wavelength slave pulse are respectively output, and the time delay between the dual-wavelength master pulse and the dual-wavelength slave pulse can be controlled by adjusting the duration of the low-voltage phase. According to the invention, ultraviolet dual-wavelength double-pulse output is realized, and master-slave pulse delay is flexible and controllable.

The present invention relates to the technical field of solid light-emitting materials, and provides a glass ceramic, a preparation method therefor and a use thereof. The glass ceramic comprises at least one of a Ba2SiO4:Eu2+ single crystal phase, or a Ba2SiO4:Eu2+ and BaSiO3:Eu2+ double crystal phase. The glass ceramic has excellent stability and light-emitting properties, can be widely used to the field of display or lighting, and is particularly applicable to the fields of outdoor display and high-power lighting.

The invention provides a combined rotating frequency doubling crystal point changing device, a point changing method and a laser. The combined rotating frequency doubling crystal point changing device comprises a refraction lens, a folded cavity mirror, a nonlinear crystal and an end mirror. The refraction lens is rotatably arranged, and fundamental frequency light enters the folding cavity mirror through the refraction lens and is reflected to the nonlinear crystal through the folding cavity mirror; the end mirror reflects fundamental frequency light entering the nonlinear crystal and frequency doubling light generated after the fundamental frequency light enters the nonlinear crystal, and the frequency doubling light is output through the output end of the nonlinear crystal. When the output point of the nonlinear crystal needs to be changed, the refraction lens is rotated by a certain angle, so that the light path of the fundamental frequency light refracted by the refraction lens is changed, and the incidence point of the fundamental frequency light and the output point of the frequency doubling light of the nonlinear crystal are further changed. The operation is greatly saved, and the implementation method is simple and rapid.

A method to generate a crystal oscillator clock having a duty cycle via a first stage of a clock circuit, double the crystal oscillator clock and inputting the doubled crystal oscillator clock into a phased-locked loop, feed back a phase-locked loop feedback clock, measure a difference in delay between a first edge of the doubled crystal oscillator clock relative to the phase-locked loop feedback clock and a second edge of the doubled crystal oscillator clock relative to the phase-locked loop feedback clock, and adjust the duty cycle of the crystal oscillator clock based on the difference in delay. A device having a detection circuit to measure a difference in delay between first and second edges of a doubled crystal oscillator clock output relative to a phase-locked loop feedback clock, and a controller to adjust the duty cycle of the clock output based on the difference in delay.

The utility model discloses a bicrystal probe assembly capable of being quickly disassembled and assembled and automatic wheel flaw detection equipment. The bicrystal probe assembly comprises a base, a probe, an elastic component, an auxiliary plate and a cover plate, the base is provided with two rows of inserting holes which are evenly arranged at intervals in the length direction of the base, and the inserting holes in the upper row and the inserting holes in the lower row are arranged in a staggered mode. The probe is inserted into each insertion hole of the base; the elastic component is arranged between the probe and the base and is used for vertically and upwards jacking the probe; the auxiliary plate is detachably mounted on the base, a plurality of dismounting holes in one-to-one correspondence with the probes are formed in the auxiliary plate, the probes are arranged in the dismounting holes in a penetrating manner, and mounting and dismounting of the probes are completed through the dismounting holes; the cover plates are located above the auxiliary plate, one cover plate corresponds to one probe, through holes are formed in the cover plates, the upper portions of the probes can stretch out of the through holes, and the cover plates are detachably connected with the auxiliary plate. According to the utility model, probe consumption and damage can be effectively reduced, and probe damage can be efficiently treated.

The utility model provides a bimorph for a wireless jacquard comb, which is characterized in that the bimorph comprises a substrate, ceramic chips and an electrode layer, gold-plated copper films are arranged at the end parts of the two surfaces of the substrate, the ceramic chips are adhered to the two surfaces of the substrate, the bottom surfaces of the ceramic chips are electrically connected with the gold-plated copper films, the electrode layer is arranged on the surfaces of the ceramic chips, and the electrode layer is arranged on the surface of the substrate. And the insulating paint is coated on the electrode layer, and the end part of the substrate, which is provided with the gold-plated copper film, is in a wedge-shaped design. The anti-corrosion capability is improved by arranging the gold-plated copper film, and meanwhile, the wedge-shaped design of the end part is convenient to insert and assemble.

The invention discloses an ultra-short pulse optical parametric oscillator based on a bicrystal structure, and relates to a laser and an assembly, and the oscillator comprises a first beam shaper (2) which is used for shaping idler frequency light (1); a second beam shaper (4) for shaping the pump light (3); a dichroscope (5); the first nonlinear crystal (6) is arranged on a light emitting path of the dichroscope (5), and the first nonlinear crystal (6) is used as an input coupling mirror of the optical parametric oscillator; the second nonlinear crystal (7) is arranged on a light emitting path of the first nonlinear crystal (6), and the first nonlinear crystal (6) and the second nonlinear crystal (7) form a resonant cavity; and the three-direction color mirror (9) is arranged on a light emitting path of the second nonlinear crystal (7) and is used for separating the pump light, the signal light (8) generated by nonlinear frequency conversion and the amplified idle frequency light (1) and transmitting and outputting the idle frequency light. The conversion efficiency of the optical parameter amplification process is improved, and the overall amplification performance of the optical parameter amplifier is guaranteed.

A laser-induced Raman and fluorescence spectroscopic test system includes a laser module, a harmonic beamsplitter, a frequency-doubling crystal, a first cavity mirror, a sample cell, a second cavity mirror, and a spectroscopic detection unit. A laser beam output by the laser module sequentially passes through the harmonic beamsplitter, the frequency-doubling crystal, and the first cavity mirror. Two sides of the harmonic beamsplitter are plated with a highly transmissive film and a highly reflective film, and the harmonic beamsplitter reflects a laser beam of a required wavelength to the sample cell. The second cavity mirror is configured for returning a laser beam from the sample cell. The harmonic beamsplitter, the first cavity mirror, the second focusing lens, and the second cavity mirror form a dual-beam waist laser resonator cavity. The first cavity mirror and the second cavity mirror are spherical mirrors and are plated with different highly reflective films.

The invention relates to the technical field of solid lasers, in particular to a large-energy green laser. The laser comprises a first pumping source, a first pumping coupling device, a second pumping source, a second pumping coupling device, a resonance assembly, a first frequency doubling crystal, a second frequency doubling crystal, a Q-switching device, a first crystal and a second crystal. The resonant assembly is used for forming a laser resonant cavity and further comprises a compensation device. According to the large-energy green laser provided by the invention, the thermal lens effect of the laser crystal can be weakened through the double-pumping double-crystal, so that the fundamental frequency light can be better amplified. And the arranged compensation device can also improve the overall thermal management of the laser by compensating the thermal lens effect, and is beneficial to outputting stable and high-energy laser.

The invention relates to the technical field of semiconductor photoelectricity, in particular to a laser-induced oxygen-zinc-magnesium nano stripe solar-blind ultraviolet photoelectric detector and a preparation method thereof. The method comprises the steps of cleaning a substrate; taking a ZnO-MgO composite target material as a sputtering source, and depositing an MgZnO thin film on the pretreated substrate by adopting a radio frequency magnetron sputtering technology; a femtosecond laser processing system is built, original laser emitted by a femtosecond laser device is subjected to frequency doubling through a frequency doubling crystal, laser pulse energy is adjusted through a polarization adjusting assembly, laser beams are focused on the surface of the MgZnO thin film on a displacement platform through an objective lens, MgZnO nano stripes are obtained through scanning processing, and surface cleaning is carried out; and evaporating a metal electrode layer on the surface of the MgZnO nano stripe by adopting a vacuum evaporation coating technology. The method has the advantages that the operation is simple, convenient and reliable, and self-assembly and form regulation and control of the nanostructure can be accurately realized; controllable doping of the Mg element can be realized by regulating and controlling the components of the target material; the process is efficient and fast, and the controllability is high.

The application is suitable for the technical field of optical devices, and provides an optical assembly, a laser and a laser processing device. The optical assembly comprises, in sequence along an outgoing light direction, a resonant cavity, an optical diffraction element, a frequency doubling crystal and a Q switch. The resonant cavity is used for emitting a light beam. The optical diffraction element is used for homogenizing the light beam. The frequency doubling crystal is used for modulating the frequency of the light beam. The Q switch is used for adjusting the direction of the light beam to control whether the light beam is emitted. The resonant cavity, the optical diffraction element, the frequency doubling crystal and the Q switch in the embodiment of the application are arranged in sequence along the outgoing light direction, so that the stability of the light beam emitted from the Q switch can be improved.

The invention relates to the technical field of ultrasonic flaw detection, in particular to an ultrasonic flaw detection method and system for cathode roller raw materials for copper foils, and the method comprises the following steps: uniformly selecting each position point on the curved surface of a cathode roller, and sequentially collecting ultrasonic signals received by each position point at each deflection angle by using a twin-crystal probe; determining a time-frequency characteristic coefficient of each ultrasonic signal; acquiring multi-angle signal distribution characteristics of each position point; determining a spatial distribution coefficient of each ultrasonic signal; and in combination with the time-frequency characteristic coefficient and the spatial distribution coefficient, correcting a threshold value in a wavelet denoising algorithm, denoising each ultrasonic signal, and carrying out ultrasonic flaw detection on the cathode roller by utilizing all the denoised ultrasonic signals. Therefore, the ultrasonic flaw detection precision of the cathode roller is improved.

A method to generate a crystal oscillator clock having a duty cycle via a first stage of a clock circuit, double the crystal oscillator clock and inputting the doubled crystal oscillator clock into a phased-locked loop, feed back a phase-locked loop feedback clock, measure a difference in delay between a first edge of the doubled crystal oscillator clock relative to the phase-locked loop feedback clock and a second edge of the doubled crystal oscillator clock relative to the phase-locked loop feedback clock, and adjust the duty cycle of the crystal oscillator clock based on the difference in delay. A device having a detection circuit to measure a difference in delay between first and second edges of a doubled crystal oscillator clock output relative to a phase-locked loop feedback clock, and a controller to adjust the duty cycle of the clock output based on the difference in delay.

1. Name of the product in this design: Bubble Wrap (Vertical Double Crystal Swimming Pool Protective Cover). 2. Purpose of this design: To cover the surface of a swimming pool. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: a 3D model.

The invention discloses a water vapor concentration detection method, device and equipment and a medium, relates to the technical field of atmospheric environment monitoring, and is applied to a laser radar comprising a laser conversion assembly. The method comprises the following steps: generating first original laser and second original laser; the water vapor absorbance of the first original laser is far greater than that of the second original laser; processing the first original laser and the second original laser by using an optical fiber amplifier and a frequency doubling crystal in the assembly to obtain first target laser and second target laser; the first target laser and the second target laser are emitted to the atmosphere, and a first echo signal and a second echo signal which are reflected back are received; and filtering an environment interference signal in the first echo signal based on the second echo signal, and determining the water vapor absorption intensity of the first target laser according to the differential signal ratio and the first target laser so as to determine the water vapor concentration information in the atmosphere. And more accurate water vapor concentration detection can be carried out.

The invention discloses a multi-source single-output green light beacon laser for space application, which is characterized in that a light source part comprises two butterfly-shaped packaging laser devices which are cold backups for each other, the butterfly-shaped packaging laser devices are solid laser devices packaged in butterfly-shaped shells, each butterfly-shaped packaging laser device comprises a semiconductor pumping chip, a shaping optical fiber, a laser crystal Nd: YVO4 and a frequency doubling crystal PPLN, and green light of 532nm is generated; in the filtering and beam combining light path part, 532nm green light emitted by each light source is respectively provided with a half-wave plate for adjusting the polarization direction, is combined into the same light path through a polarization splitting prism, is filtered by a light filter, enters a multimode optical fiber through an optical fiber collimator, and is divided into two paths through an optical fiber coupler; one path is used for monitoring the output power and health state of the laser in real time, and the other path is used as main beacon light. The problem of performance reduction caused by the overheating phenomenon of the light-emitting unit is effectively solved, high-power output can be kept for a long time, and meanwhile the overall light weight and flexibility of the laser are considered.

The present invention relates to the technical field of spectrum testing. Disclosed is a laser-induced Raman and fluorescence spectrum testing system, comprising a laser module, a harmonic separator mirror, a frequency-doubling crystal, a first cavity mirror, a sample cell, a second cavity mirror, and a spectrum detection unit, wherein laser light emitted from the laser module sequentially passes through the harmonic separator mirror, the frequency-doubling crystal, and the first cavity mirror; the two surfaces of the harmonic separator mirror are respectively coated with a highly transmissive film and a highly reflective film, and the harmonic separator mirror reflects laser light having a required wavelength to the sample cell; the second cavity mirror is used for reflecting the laser light from the sample cell back. The harmonic separator mirror, the first cavity mirror, a second focusing lens, and the second cavity mirror in the present invention form a dual-beam-waist laser resonant cavity. The first cavity mirror and the second cavity mirror are both spherical reflective mirrors, and are respectively coated with a highly reflective film. The first cavity mirror is confocal with a first focusing lens, and the second cavity mirror is confocal with the second focusing lens. Two beam waist focuses of the laser resonant cavity are respectively located at the positions of the frequency-doubling crystal and the sample cell, so as to achieve the optimal frequency-doubling efficiency and sample excitation efficiency.

The invention relates to the technical field of laser, and discloses a high-power yellow-green laser generation method, which comprises the following steps: generating pump light through a first seed source, and generating signal light through a second seed source; after the pump light and the signal light are mixed through the first wavelength division multiplexer, the pump light and the signal light are combined with the light of the first pump source in the beam combiner, and then are subjected to power amplification through the first ytterbium-doped optical fiber to obtain high-power laser; after collimation by the collimator and color separation by the first dichroic mirror, frequency doubling is carried out by the frequency doubling crystal, and finally, high-power yellow-green laser is output by color separation by the second dichroic mirror. The invention discloses an optical fiber laser for generating high-power yellow-green laser, which reduces the number of core devices in an optical path structure, simplifies the optical path structure and control logic, reduces the hardware cost and assembly debugging cost of equipment, and improves the production efficiency. The stimulated Brillouin threshold value of the laser is effectively improved, broadening in the spectrum amplification process is restrained, and meanwhile the stable and good time-domain characteristic can be kept.

The invention relates to the technical field of optics and laser, in particular to a laser frequency doubling walk-off angle compensation method and device, and the method is applied to a target optical path comprising a laser source, a frequency doubling crystal and a target optical wedge. Fundamental frequency light emitted by the laser source is controlled to enter the frequency doubling crystal; frequency doubling light emitted by the frequency doubling crystal and the fundamental frequency light are controlled to be incident to the target optical wedge, and a target walk-off angle exists between the fundamental frequency light and the frequency doubling light in the frequency doubling crystal; the wedge angle of the target optical wedge is determined according to the target walk-off angle, the refractive index of the target optical wedge to light with different wavelengths and a preset propagation distance, and the fundamental frequency light and the frequency doubling light emitted by the target optical wedge coincide at the preset propagation distance. According to the embodiment of the invention, the method can achieve the superposition of the fundamental frequency light and the frequency doubling light at the preset propagation distance only through the target optical wedge, and effectively reduces the number of components of a target optical path and the occupied space.

1. The name of the design product: double crystal monochromator (single station). 2. The use of the design product: for monochromatizing continuous synchrotron radiation. 3. The design points of the design product: in shape. 4. The picture or photo that best shows the design points: perspective view 1.

The invention relates to a high-power green laser synthesis system based on a rotary frequency doubling crystal and multiple beams of infrared pulse laser, and belongs to the technical field of laser. The system comprises a multi-beam pulse infrared laser device, a frequency doubling crystal module, an annular rotating mechanism, a beam combining device, a continuous infrared laser device, a laser frequency regulation and control device and a rotating driving control system. The four beams of pulse infrared laser sources are symmetrically arranged along the circumferential edge, and periodically staggered output is realized through frequency regulation and control; the multiple frequency doubling crystals are distributed along the rotating circular ring at equal intervals and are sequentially aligned with laser pulses under driving of the rotating mechanism, and efficient frequency doubling is achieved. The center continuous infrared laser generates stable green light through frequency doubling of the fixed crystal. Finally, the green light generated by the multiple frequency doubling crystals and the central green light are integrated into a single light beam through a beam combining device to be output. According to the system, the power upper limit and the stability of green laser are remarkably improved through energy sharing of polycrystals, rotary dynamic matching and annular cooling, and the problems that existing green laser is limited in power and serious in heat effect are solved.

The utility model discloses a fine-adjustable bicrystal monochromator for an X-ray diffractometer, belongs to the technical field of X-rays, and aims to solve the problem that a traditional U-shaped crystal monochromator is high in price due to the fact that the difficulty of a processing mode is high and the yield is low in the prior art. The utility model relates to a fine-adjustable bicrystal monochromator for an X-ray diffractometer. The fine-adjustable bicrystal monochromator comprises a U-shaped bicrystal fixing piece; a first crystal; the crystal adjusting mechanism is arranged below the first crystal, the crystal adjusting mechanism is fixed on one side of the U-shaped double-crystal fixing piece, and the first crystal swings around the X axis, the Y axis and the Z axis through the crystal adjusting mechanism; the crystal face of the second crystal and the crystal face of the first crystal are oppositely arranged; the first crystal and the second crystal are complete crystals of the same kind, and two opposite crystal faces have the same parallelism; the balancing weight is arranged below the second crystal; and the balancing weight is fixed on the other side of the U-shaped double-crystal fixing piece.

This invention discloses a multi-stage cascaded laser frequency doubling device, belonging to the field of laser frequency doubling technology. It includes a front-end frequency doubling module and at least one cascaded frequency doubling module arranged sequentially along the optical path. The cascaded frequency doubling module includes a second-harmonic crystal, a third-harmonic crystal, a beam splitter, a delay adjustment device, and a beam combiner. The front-end frequency doubling module, beam splitter, second-harmonic crystal, beam combiner, and third-harmonic crystal are connected sequentially. By extending the multi-stage continuous cascaded crystal architecture, the long crystal is split into a sequence of thin frequency doubling crystals, suppressing time drift and pulse broadening. Each stage is equipped with a multi-band fully transparent film system to reduce dispersion. Furthermore, a beam splitting and beam combining bypass and dynamic time delay compensation are designed to achieve precise spatiotemporal beam combining of ultraviolet light, enabling femtosecond lasers to possess both high efficiency, low broadening, and excellent pulse quality.

The invention belongs to the technical field of lasers, and provides a 486nm laser based on Raman laser frequency tripling and application, the 486nm laser is used for outputting 486.1 nm target blue light, and the 486nm laser comprises a fundamental frequency light source, a frequency tripling module and a dichroscope; the base frequency light source outputs base frequency light of 1458.3 nm, frequency doubling is carried out on the base frequency light of 1458.3 nm with a part of power in the frequency doubling crystal to generate frequency doubling light of 729.15 nm, and sum frequency is carried out on the base frequency light of 1458.3 nm with the other part of power and the frequency doubling light of 729.15 nm in the sum frequency crystal to generate target blue light of 486.1 nm; and 486.1 nm target blue light is separated and output by using a dichroscope. The blue light source with high power, high light beam quality, high stability and narrow linewidth can be realized, and a high-performance light source is provided for underwater application scenes such as underwater detection, communication, photoelectric countermeasure and diving exploration.

The invention relates to the technical field of ultraviolet lasers, and discloses a packaging method, device and equipment for a frequency doubling cavity of an ultraviolet laser and a medium. The method comprises the following steps: providing a laser frequency doubling cavity shell and a laser frequency doubling cavity upper cover; the frequency doubling crystal module and the spectroscope or the reflector are arranged in the laser frequency doubling cavity shell; the laser frequency doubling cavity upper cover and the laser frequency doubling cavity shell are connected in a sealed mode; wherein the light path space transmitted by the laser beam is the space corresponding to the transmission path of the laser beam in the frequency doubling cavity, the space occupied by the frequency doubling crystal module is the space actually occupied by the frequency doubling crystal, the assembling structure of the frequency doubling crystal and the temperature control system, and the adjustment space is the minimum necessary space meeting the adjustment requirement of a spectroscope or a reflector. Therefore, the volume of the sealed internal space is only the minimum volume for accommodating an optical path and an optical device and necessary adjustment. The internal space of the frequency doubling cavity is precisely designed, so that the volume of gas needing to be cleaned is greatly reduced, the internal gas volume is reduced, and the gas replacement efficiency is remarkably improved.