51results about How to "Improve frequency conversion efficiency" patented technology

The invention discloses an intra-cavity frequency doubling green-ray fiber laser with a full optical fiber structure. The laser comprises a pumping assembly, a first fiber bragg grating, a third fiber bragg grating, a second fiber bragg grating and a first tail fiber, wherein the output end of the pumping assembly is connected with the first fiber bragg grating; the first fiber bragg grating, the third fiber bragg grating and the second fiber bragg grating are arranged concentrically; a double-pack yttrium-doping optical fiber is connected between the first fiber bragg grating and the third fiber bragg grating; an intra-cavity frequency doubler is connected between the third fiber bragg grating and the second fiber bragg grating; the output end of the second fiber bragg grating is connected with the first tail fiber; and all the components are connected in a molten connecting mode. According to the invention, an optical fiber laser technology and a full-solid intra-cavity frequency doubling technology are combined by the laser, intra-cavity frequency doubling is realized by adopting the full optical fiber structure, the laser outputs at the green ray wave band, the defects caused by the formation of discrete components for the existing laser are overcome, the optical conversion efficiency is improved, the output light bundle has good quality, the light-light conversion efficiency is high, the structure is compact, the performances are stable, and the frequency doubling efficiency is approximate to 100%.

The invention provides a device for generation of high-power vacuum ultraviolet laser by direct frequency multiplication and a method thereof. The device comprises a laser pumping source, a direct frequency multiplication device, a vacuum cavity, a power measuring system, a light beam shaping system and a four-dimensional pre-adjusting flat turning table. The laser pumping source is a narrow line-width all-solid-state ultraviolet laser pumping source. The light beam shaping system is arranged between the laser pumping source and the vacuum cavity. The four-dimensional pre-adjusting flat turning table is fixed in the vacuum cavity. The direct frequency multiplication device is fixed on an adapter plate. The method comprises the steps that phase matching under the low-power pumping condition is firstly realized, based on which the angle of the direct frequency multiplication device is pre-adjusted so that phase matching under the high-power condition is realized in advance. High-power hundred milliwatt and watt level vacuum ultraviolet laser output can be realized so that the generated vacuum ultraviolet laser has characteristics of being narrow in line-width, high in frequency multiplication conversion efficiency, high in frequency multiplication output power, stable in output power under high power and practical.

The invention relates to a frequency converter based on a ridge-type lithium niobate monocrystal thin-film waveguide integrated periodic domain reversal structure, and preparation thereof. The preparation comprises the following steps: preparing a periodic structure with domain reversal region duty ratio as 0.5 on a lithium niobate monocrystal thin-film surface by using the same laser processing parameter; and then preparing ridge-type waveguide on the lithium niobate monocrystal thin-film by applying femtosecond laser direct writing or precise diamond knife-cutting technology, and integratingon a pre-processed periodic structure; and then performing polishing treatment on two X end surfaces of the LNOI, cleaning and obtaining polished surfaces; and then integrating a semiconductor laserand an optical fiber coupling system, the lithium niobate monocrystal thin-film waveguide with the periodic domain reversal structure and an optical filter, thereby realizing the frequency conversionfunction of the laser with specific wavelength. The frequency converter disclosed by the invention has the features of being high in conversion efficiency, good in beam quality and long in life; and the product is mainly applied to the optical fiber communication, the electronics device preparation, the information storage, the infrared detection and like fields.

The invention relates to a three-band pulsing laser, comprising a pulsed laser seed source, a laser amplifying device and a three-band output device; wherein the pulsed laser seed source is used for generating seed laser, the laser amplifying device is used for receiving and amplifying the seed laser to obtain fundamental laser; the three-band output device is used for frequency doubling on the fundamental laser and for frequency doubling on the frequency-doubled laser again to obtain fourfold laser, and the remanent fundamental laser, the remanent frequency-doubled laser and the obtained fourfold laser are output by the method of beam splitting. The invention realizes three-band output, and the cavity structure can ensure high energy and narrow pulse width three-band laser output and also can reduce element damage. Besides, the structure of the invention is simple and compact, installation and debugging is easy, and industrialized design can be realized.

The invention discloses a method for preparing a KTP crystal capable of resisting gray track, comprising the following steps that: 1) KH2PO4 and TiO2 as raw materials used to synthesize a KTiOPO4 crystal, and K2HPO4 as the raw material used to synthesize a K4P2O7(K4) solvent are mixed according to a certain ratio, and the initial growth mol ratio of the KTiOPO4 to the K4P2O7 obtained after the chemical reaction is about 0.8; 2) the mixed raw materials are put in a platinum crucible and the solution filling amount is between 75 and 85 percent; 3) the platinum crucible is put in a furnace body, a temperature gradient of the furnace is set to be between 3 and 8 DEG C per 10 centimeters, and the furnace is heated so that the raw materials are melted and react to form an even and stable high temperature solution; and 4) the seed crystal is put in the high temperature solution, the temperature is reduced at a temperature gradient of between 1 and 8 DEG C per 100 hours, and the KTiOPO4 crystal is grown at a temperature interval of between 850 and 820 DEG C. The method utilizes the K4P2O7 solvent to prepare the KTP crystal, reduces the absorption coefficient of the KTP crystal, and has evident anti-gray track performance; therefore, the frequency multiplication conversion efficiency of the KTP is improved further, the KTP crystal has good voltage withstanding and modulation performances and can be used as an electrooptical crystal.

The invention provides a visible ultraviolet band optical frequency converter. The processing period of a nonlinear optical crystal is controlled to provide an additional period phase to meet a phasematching condition so as to realize effective optical frequency conversion. The additional period phase is characterized in that phase gratings periodically arranged according to different refractiveindexes are formed in the crystal through technologies, including laser micro-processing, ion etching and the like, a nonlinear frequency conversion inverse process is avoided through the periodic structure damage of the crystals in the phase gratings and an additional period phase is provided, phase mismatch caused by the insufficient double refraction of the nonlinear optical crystal is avoided,and efficient frequency doubling or sum frequency output is realized. By use of the optical frequency converter, the nonlinear optical material can be optimized, the proper crystal can be selected according to required wavelength, and the additional period phase matched with the technologies can be provided so as to realize the effective output of specific wavelength. A new variety is provided for the nonlinear optical frequency converter, and the optical frequency converter has the advantages of high optical frequency conversion efficiency, easiness in preparation and the like.

The present invention relates to a novel device of dual wavelength laser frequency doubling. The corresponding phase matching angles of the laser of different wavelength are different in nonlinear optical crystal, which is a problem necessitating consideration when designing a device which can realize simultaneous frequency doubling to dual wavelength laser. By means of geometric calculation and cutting shape design, a device which can realize simultaneous frequency doubling to dual wavelength laser is acquired. The laser of dual wavelength is made to transmit alongside the phase matching direction of the laser of one wavelength to generate the frequency doubled light of the wavelength. When reaching the end face of crystal the laser bundle is shifted to travel along the phase matching direction of the laser of the other wavelength by reflection, thus acquiring the frequency doubled light of corresponding wavelength.

The invention relates to a preparation method of gray track resistance KTiOPO (GTR-KTP) crystals. The method comprises the following steps: firstly preparing a KH2PO4 crystal material, and then carrying out sectional heating to form an even and stable high-temperature solution under a super environment; adopting a method of combining the top end with lifting to grow the GTR-KTP crystals. According to the KTP crystals prepared by the preparation method, an absorption coefficient of the KTP crystals is reduced; a gray track can be effectively prevented, so that the frequency doubling conversion efficiency of the KTP crystals is obviously enhanced; the GTR-KTP crystals are irradiated by a 100mw and 532nm of green light within 1000 seconds in a test; absorption of the system is basically kept stable; a good gray track resistant effect is displayed.

The invention discloses a large-aperture laser frequency conversion system with efficient frequency multiplication performance. The large-aperture laser frequency conversion system comprises a deformable mirror, a driver of the deformable mirror, a frequency multiplication crystal, a calculation control processor, a convergent lens and a machine shell assembly. The deformable mirror, the frequencydoubling crystal and the convergent lens are arranged on the same optical axis. The included angle between the mirror surface normal of the deformable mirror and the incident light direction is 45 degrees, and the optical axes of the mirror surface normal of the frequency doubling crystal and the convergent lens coincide with the incident light direction. The frequency doubling crystal has surface shape distortion in an actual working environment, and plane waves deviate from angle phase matching during incidence, so that the frequency doubling efficiency is reduced. According to the invention, through offline measurement before working, a distorted surface shape of the frequency doubling crystal and a response function of the deformable mirror and the driver thereof are obtained. The driving voltage required by the deformable mirror driver for compensating the surface shape distortion of the frequency doubling crystal and correcting the output light wavefront is calculated, and the driver is controlled to load the calculated driving voltage during working, so that the effects of realizing accurate angle phase matching, improving the frequency doubling efficiency and improving theoutput light collimation can be achieved.

The embodiment of the invention provides a nonlinear frequency conversion crystal. The nonlinear frequency conversion crystal comprises an incident plane, a first inclined plane, a second inclined plane and a spherical surface, wherein the phase matching direction of the crystal is parallel to the central axis of the crystal, the incident plane is vertical to the central axis, the first inclined plane and the second inclined plane are arranged on two sides of the central axis oppositely, and an inclined angle between the first inclined plane and the central axis and an inclined angle between the second inclined plane and the central axis are the same; the spherical surface is connected with the first inclined plane and the second inclined plane respectively, and the center of a sphere of the spherical surface is positioned on the central axis. According to the crystal provided in the embodiment of the invention, two times of frequency conversion are realized on a return path, and moreover, one time of focusing is realized in the process of realizing frequency conversion every time, so that the frequency conversion efficiency can be greatly improved, and the proportion of light beams after frequency conversion in light beams emitted from the incident surface of the crystal is increased finally.

The invention discloses a laser emitting device, which is used for generating 780nm laser in a direct frequency doubling mode. The device comprises a semiconductor laser, the wavelength of output laser being 1560 nm, and line width of output laser being smaller than 10 kHz; a double-concave-surface lens frequency doubling resonant cavity, comprising a first concave surface lens and a second concave surface lens which are oppositely arranged based on concave surfaces, a high-reflection film with the wavelength of 780 nm and an antireflection film with the wavelength of 1560 nm being evaporatedon the surface of the first concave surface lens, and a high-reflection film with the wavelength of 1560 nm and an antireflection film with the wavelength of 780 nm being evaporated on the surface ofthe second concave surface lens; and a frequency doubling crystal, the surface of the frequency doubling crystal being evaporated with antireflection films with wavelengths of 1560nm and 780nm, and the frequency doubling crystal being arranged between the first concave lens and the second concave lens and being used for carrying out frequency doubling treatment on the laser from the semiconductorlaser. According to the laser emitting device provided by the invention, emission of 780nm narrow-linewidth laser obtained by direct frequency multiplication of 1560nm is realized, and the frequency multiplication light width is further narrowed along with the narrowing of the signal light width.

The invention discloses a rear end pumped miniaturized visible light wavelength range surface-emitting semiconductor laser comprising a pump light source, a collimating focusing lens group, a heat sink with a light through hole, a semiconductor gain chip, a reflection flat sheet, nonlinear crystal and a coupling output mirror which are arranged from the back to the front along the axial direction of the optical axis. The semiconductor gain chip comprises a reflecting film having high transmittance for the pump light and high reflectance for the fundamental frequency light and a quantum well active region. A film layer having high reflectance for the frequency doubled light and high transmittance for the fundamental frequency light is coated on the rear side of the reflection flat sheet. All the elements are arranged on the same axis which is also the optical axis of the laser resonant cavity so that the quality of the light beams outputted by the laser is enabled to be excellent, adjustment of the device is enabled to be easier than that of any other visible light laser, the mechanical performance of the device is quite stable, the rear end pump mode is combined with the linear structure, the device is enabled to be quite miniature and thus the laser has quite wide application in multiple desktop type comprehensive scientific research instruments.

The invention discloses a long-pulse green laser vessel therapeutic instrument. The long-pulse green laser vessel therapeutic instrument comprises an M1 total reflector, an AO acoustooptic modulator, an Nd:YAG laser crystal, a KTP frequency doubling crystal and an M3 output mirror which are arranged on an optical path in sequence, wherein an M2 middle mirror is arranged between the Nd:YAG laser crystal and the KTP frequency doubling crystal. The long-pulse green laser vessel therapeutic instrument is same as a common vessel therapeutic instrument with a straight cavity (except length), but the long-pulse green laser vessel therapeutic instrument has a foldable double-channel frequency doubling cavity. In addition, the long-pulse green laser vessel therapeutic instrument is suitable for mass production. Because laser oscillation only depends on the two lenses of the M1 total reflector and the M3 output mirror, the long-pulse green laser vessel therapeutic instrument is easily adjusted, and the consistency problem of mass production is solved.

The invention provides a nonlinear optical crystal beryllium fluorocarbonate with the chemical formula Be2CO3F2 (abbreviated as BCF). Research shows that the BCF crystal of the invention has stronger nonlinear optical effect and greater birefringence than the KBBF crystal. efficiency, higher frequency doubling conversion efficiency, higher deep UV output power, stronger mechanical properties, better machinability, and higher resistance to laser damage; it can be used as an excellent UV and deep UV nonlinear optics Crystals and birefringent crystals, and can be widely used in various nonlinear optical crystal materials and two-dimensional materials.