334 results about "Lithium niobate crystal" patented technology

The making process of lithium niobate modulator includes making substrate with lithium niobate crystal with proper crystal cutting direction and electric field utilizing direction; making light waveguide on the lithium niobate crystal; making modulating electrodes including central signal electrode and earth electrode and to form push-pull structure with the light waveguide; making microstrip matching structure in the input and output of the modulating electrodes; and setting buffering layer structure between the modulating electrode and light waveguide. Owing to the smart design of the modulating electrodes, the light waveguide and the matching structure in between, the lithium niobate modulator has high modulating rate, low insertion loss, high extinction ratio, low hemi-wave voltage, less electric reflection, and high reliability.

The invention relates to the non linear optical frequency conversion. To realize output of high power THz wave which can be continuously tuned, and stable running at room temperature, the technical scheme used by the invention is that: a tunable terahertz radiation source based on difference frequency cherenkov effect is composed of a laser device, a frequency doubling crystal, a double wavelength parametric oscillator, a harmonic mirror, a polarization filter, a combined beam mirror, a column lens and a difference frequency crystal; the harmonic mirror is placed between the frequency doubling crystal and the double wavelength parametric oscillator; the double wavelength parametric oscillator is II type phase matching KTP (Potassium Titanyl Phosphate) crystal OPO (Optical Parametric Oscillator); the polarization filter, the combined beam mirror and the column lens are arranged between the parametric oscillator and the difference frequency crystal; the difference frequency crystal is amagnesium oxide doped lithium niobate crystal with molecular formula of MgO:LiNbO3 or MgO:LN, and the generated THz wave is coupled and output by an Si prism on the side surface of the difference frequency crystal. The tunable terahertz radiation source based on difference frequency cherenkov effect is mainly applied to the optical frequency conversion.

A method and a system are implemented in the fabrication of a portable high power terahertz beam source that can produce a tunable, high power terahertz beam over the frequency from 0.1 THz to 2.5 THz. The terahertz source employs a recycling pump beam method and a beam quality control device. The beam quality control device may or may not be required for a high power terahertz beam generation. In exemplary embodiments, a lithium niobate (LiNbO₃) crystal or a lithium niobate crystal doped with 5% magnesium oxide (LiNbO₃:MgO) can be used. Other nonlinear optical crystals, including GaSe can be used in place of the LiNbO₃ crystal. Through proper alignment of a pump beam, along with recycling a pump beam, high conversion efficiency is achieved, and a high output power beam is produced at terahertz frequencies.

In a method of producing a lithium niobate substrate by the use of a lithium niobate crystal grown by the Czochralski process, the lithium niobate crystal is heat-treated at a temperature of from 300° C. or more to less than 500° C. in the state the lithium niobate crystal is buried in a powder constituted of at least one element selected from the group consisting of Al, Ti, Si, Ca, Mg and C, or in the state the lithium niobate crystal is held in a container constituted of at least one element selected from the group consisting of Al, Ti, Si, Ca, Mg and C.

The invention includes pumping source, optical couple lenses, input mirror and output mirror, nonlinear crystal C2 and its temperature controlling stove. Aperiodic poled Lithium Niobate crystal C1 is mounted between input mirror and output mirror and its temperature controlling stove with 100 Deg C.-200 Deg C. working temperature. When the pump beam lambdap = 1064 nm, the aperiodic poled crystal takes two signal beams lambda1=1500nm and lambda2=1510nm to make incidence to non linear crystal C2. 1450-1550nm reflection reducing coating film is coated on end face of non linear crystal. Poled period is 35um,a=23DEG. When working temperature of temperature controlling stove of Non linear crystal C2 is 100 Deg C.-200 Deg C., the frequency range produced by difference frequency of non linear crystal C2 is 1.19THz-1.45THz Terahertz wave.

The invention relates to a blackening method for a lithium tantalate or lithium niobate crystal substrate. The method comprises the following steps: preparing a mixed system from an elemental material with deoxidation ability and a mixture of a glue and a certain proportion of lithium carbonate powder; uniformly coating both sides of a to-be-treated lithium tantalate or lithium niobate crystal substrate by using a screen printing method; and placing the substrate in a stainless steel container, then putting the container into a heat treatment furnace, and carrying out reduction treatment on the to-be-treated lithium tantalate or lithium niobate crystal substrate in a nitrogen atmosphere with a flow of 6 L/min to 10 L/min under and at a temperature below the Curie temperature of the to-be-treated lithium tantalate or niobate crystal substrate. In the mixed system, organic silicone glue is used as glue; and the elemental material with deoxidation ability is Zn powder which accounts for 35% or less of the mass of the mixed system. According to the invention, reduced blackening treatment of the lithium tantalate or lithium niobate crystal substrate is carried out under Curie temperature conditions; and through blackening treatment, the pyroelectric properties of the substrate is reduced, and thus, manufacturing cost for a SAW filter is lowered and the production efficiency of the SAW filter is improved.

The invention discloses a high-efficiency super-smooth chemical mechanical polishing method for a lithium niobate crystal and belongs to the technical field of ultraprecision machining of nonlinear optical crystals. The high-efficiency super-smooth chemical mechanical polishing method is characterized in that a sample is a lithium niobate crystal; the lithium niobate crystal is processed by adopting a method of combining grinding of bonded abrasives, polishing of a retaining ring hard polishing pad and chemical mechanical polishing of a retaining ring soft polishing pad, wherein the hard polishing pad is a synthetic leather or polyurethane polishing pad; the soft polishing pad is non-woven fabric or fuzzy polishing pad; a pH value of a chemical mechanical polishing solution is 10.2-10.6; the chemical mechanical polishing solution contains four kinds of cerium oxide, silicon oxide, potassium hydroxide, sodium hydroxide, barium hydroxide, potassium permanganate, hydrogen peroxide, citric acid, acetic acid and oxalic acid; the grinding time of the bonded abrasives is 15-25 minutes; the polishing time of the hard polishing pad is 50-70 minutes; the chemical mechanical polishing time is 3-6 minutes; the removal rate of materials for chemical mechanical polishing is 420-460nm/min; the planeness of the polished lithium niobate is 3.8-5.5[mu]m; the surface roughness Ra of the polished lithium niobate is 0.35-0.5nm and the PV value of the polished lithium niobate is 3.8-6nm. The high-efficiency super-smooth chemical mechanical polishing method disclosed by the invention has the beneficial effect that a high-efficiency super-smooth polishing method of a nonlinear optical crystal is realized.

The invention provides a preparation apparatus and method of a lithium niobate crystal nano domain structure and is intended to solve the difficulty of the prior polarization technology in preparing a nano domain structure in lithium niobate crystal; the preparation apparatus and method are suitable for the preparation of nano domain structures in the field of ferroelectric crystal nano domain engineering, particularly for Z-tangential congruent lithium niobate crystal, magnesium-doped lithium niobate crystal and the like. The preparation method comprises the steps of first, constructing a domain wall structure in lithium niobate crystal; second, thermally treating a sample; third, secondarily polarizing the sample. By changing thermal treatment temperature and thermal treatment time, it is possible to prepare nano domain structures different in size; the size of the domain structures is generally of hundred nanometers level, and the depth thereof is of hundred micrometers level; by using the method, it is possible to prepare high-quality nano domain structures hundred micrometers in length; the method has the advantages that the method is simple to perform and is suitable for preparing nano domain structures in batch on a large scale.

The present invention relates to one kind of electrooptical angle measurer and belongs to the field of electrooptical detection technology. The present invention aims at real-time monitoring coaxial relative rotation angle of emitting platform and receiving platform separated by certain distance to realize second level angle measurement. The technological scheme of the present invention includes measurer comprising three parts of emitting part, receiving part and electric control part; grating outer-cavity semiconductor laser as light source; electrooptical lithium niobate crystal for loading angle information; polarizing light splitter and light detector for demodulating information; and differential processing technology used in processing obtained electrical signal. The present invention can complete angle measurement in second level precision with an angle measurer with compact structure, high vibration resistance and high long term stability.

The invention discloses a device and a method for preparing a waveguide and a grating by femtosecond laser etching. The device is formed by sequentially connecting a femtosecond laser, an optical polarizer, a beam splitter, a first reflector, a second reflector, a third reflector, a microobjective, lithium niobate crystals, a precision rotating platform, a three-dimensional electrical translation stage, an optical power meter and a computer. The device and the method solve the problem of how to control the laser condition and achieve an effect of using one femtosecond laser light source and only one set of processing equipment for simultaneously implementing preparation of the optical waveguide and the grating.

The 2D laser beam scanner consists of planar diffraction grating, collimating lens, horizontal scanning assembly on a socket, and vertical scanning assembly on a socket successively arranged in the light beam forward direction. The planar diffraction grating is in the focus plane of the collimating lens. The horizontal scanning assembly is one crystal plate array comprising several lithium niobate crystal plates in the same cutting structure and arranged in the optical axle direction, and the lithium niobate crystal plates have electrodes in sockets and in the equi-different lengths. The vertical scanning assembly has the same structure as the horizontal one but in vertical direction. The present invention has the features of fast scanning speed, high precision, no mechanism motion, simple structure, high stability and reliability and certain integration level.

The invention provides a multiplier enhancing method based on periodically poled lithium niobate, and belongs to the technical field of optical information processing. The method includes firstly, performing room temperature electric field polarization on lithium niobate crystals, changing the polarization direction of the electric domain in a negative domain region of the +Z face of the crystals, and performing vacuum coating sputter electrode on two Y-directional sides of the crystals; then irradiated the crystals with a normal light and applying voltage of the two Y-directional sides of the lithium niobate crystals through a high voltage source simultaneously, and realizing ordinary light multiplier enhancement through produced slow light effects. According to the method, the quasi-phase matching technique (QPM) is creatively combined with effective light power enhancement resulted from the slow light effects.

The invention relates to a signal photon detector based on polarization unrelated frequency up-conversion; the signal photon detector comprises a lithium niobate crystal which is formed by periodically superposing four parts and is periodically polarized, wherein for a first part and a fourth part, the periodic structures are same, the period length is lA and meets the quasi-phase matching condition of frequency up-conversion, and the period number is NA so that all signal lights can be converted into sum frequency lights; a second part is in a periodic structure used by reciprocal lattice vectors for compensating mismatching of wave vectors coupled and polarized by signal lights, and the period length is lB and meets the phase matching condition of signal light polarization rotation; and a third part is in a periodic structure used by reciprocal lattice vectors for compensating mismatching of wave vectors coupled and polarized by sum frequency lights, the period length is lC and meets the phase matching condition of signal light polarization rotation. An external direct-current power supply is applied to y-surfaces of the second part and the third part of a sample so as to realize the periodic modulation of optical coefficients, thereby leading the polarization direction of corresponding light waves to rotate. The signal photon detector is practicable in preparation and has wide application prospect in fields of quantum communication and photo-communication.

The invention relates to a luminescent material and a preparation method thereof, particularly relates to a zirconium-ytterbium-holmium tri-doped lithium niobate crystal high-upconversion luminescent material and a method for preparing the same, and aims to solve the technical problems of low luminous efficiency and poor light damage resistance of existing LiNbO3:Ho crystal. The zirconium-ytterbium-holmium tri-doped lithium niobate crystal high-upconversion luminescent material is made of Li2CO3, Nb2O5, ZrO2, Yb2O3 and Ho2O3. The preparation method includes: weighing, mixing, presintering, seeding, shoulder expanding, isometric growing and crystal polarizing, so that the zirconium-ytterbium-holmium tri-doped lithium niobate crystal high-upconversion luminescent material can be obtained. The light damage resistance of the crystal is greatly improved when 2mol%-6mol% ZrO is doped in the zirconium-ytterbium-holmium tri-doped lithium niobate crystal high-upconversion luminescent material, and improved by three orders of magnitude as compared with that of crystal with 0mol% ZrO doped, and the upconversion luminescence intensity of the doped crystal is gradually improved along with increase of Zr ionic concentration.

The invention provides a preparation method of p-type and n-type conductive lithium niobate nanowires. The preparation method comprises the following steps: step 1, uniformly heating a multi-domain lithium niobate crystal for a certain time by using thermal immobilization technology, and naturally cooling to room temperature, so that protons in the crystal are fixed in a domain wall region; 2, carrying out primary polarization on the prepared lithium niobate crystal by using electric polarization technology; and 3, carrying out secondary polarization on the prepared lithium niobate crystal byutilizing electric polarization technology, so that the conductivity type of nanowires prepared in the step 2 can be changed, and the conversion of p-type and n-type conductive carrier types can be realized through one-time polarization inversion. According to the method, the regulation and control technology of transporting carriers in the lithium niobate crystal at nanoscale is achieved, and theregulation and control problem of the electrical properties of lithium niobate at nanoscale is solved.

The present invention belongs to the field of crystal material technology, and includes mainly setting one support disc inside ceramic crucible, setting one refractory cylinder vertically on the disc, fixing one noble metal ring horizontally on the cylinder, hanging one noble metal cylinder on inner edge of the ring, and making the noble metal crucible rotate around the support shaft and move up and down and the heating winding move up and down with the crucible. During melting material, the noble metal crucible is separated from the noble metal cylinder; and during growing crystal, the noble metal cylinder separates the noble metal crucible into two regions, growth region and melt region. The present invention has the advantages of high material melting efficiency, homogeneous stirring, less volatilization of lithium oxide, easy regulation of temperature field, being favorable to stable crystal growth, etc.

The invention relates to a large-scale silicon-based lithium niobate thin film electro-optic modulator array. The invention has the advantages that the difficulty of preparation process of a lithium niobate crystal layer is reduced through a structural design, the precision requirement of bonding of lithium niobate and silicon is reduced, the preparation and the bonding of a large-scale array typelithium niobate crystal layer can be simultaneously completed at one time, and the production efficiency of the silicon-based lithium niobate thin film electro-optic modulator array is greatly improved; and through the structural design and optimization of the silicon crystal layer, light can be naturally alternated and transmitted mutually in silicon waveguide and lithium niobate waveguide, anda high-performance lithium niobate thin film electro-optic modulation effect is realized. In addition, the method utilizes the maturity advantage of a standardized silicon-based integration technologyand concentrates a complex chip preparation process on the silicon crystal layer, thereby reducing the process error in the chip manufacturing process and ensuring the performance stability of the whole silicon-based lithium niobate thin film electro-optic modulator array.

A Mg-doped lithium niobate crystal with periodically polarized microstructure is prepared frmo Mg-doped lithium niobate powder through growing crystal by Czochralsk method, gas-phase balanced diffusion and low-voltage polarizing at room temp. to make the crystal have periodic structure. It can be used to make optical device. Its advatages are high resistance to optical damage and high uniformity.

The invention discloses a double blended lithium niobate crystal and preparing method in single crystal growth domain, which comprises the following steps: (1) setting component of the crystal as LiaNbbO3:FecCod; setting a as 0. 93800; setting b as 1. 00000; setting c as 0. 00005-0. 00075; setting d as 0. 00005-0. 00050; batching; mixing; calcining; (2) melting; lifting and pulling crystal; (3) proceeding single design; annealing; cutting film; buffing. This invention possesses higher non-volatile storing sensibility, which can be used to canned data, integrated optics and finance aspects.

The invention discloses a method for manufacturing a near-stoichiometry PPLN all-optical wavelength converter low in Mg doping. The method comprises the steps that firstly, a Z-cut congruent lithium niobate chip with two faces polished is selected, and after the -Z surface of the chip is locally doped with magnesium, a Ti diffusion strip optical waveguide is manufactured on the -Z surface of the chip doped with Mg; secondly, periodical polarization is conducted on the +Z surface of the chip, a periodical array metal optical grating electrode composed of a long aluminum strip is formed, a near-stoichiometry lithium niobate crystal doped with Mg is obtained by means of the rich-lithium VTE technique, and liquid polarization is conducted on the crystal at the indoor temperature by means of a liquid electrode polarization device, so that a periodical crystal superlattice is obtained; finally, the obtained product is doped with Mg, the PPLN crystal is packaged, and near-stoichiometry PPLN all-optical wavelength converter low in Mg doping is obtained. Compared with the prior art, the method has the advantages that cost is low, the use conditions and the application fields of the wavelength converter are widened, the wavelength converter can be integrated with other devices easily, the degree of integration of the devices is improved, coupling losses and transmission losses are greatly reduced, and the system stability is high.

The invention discloses a real-time controllable micro-droplet jetting device and method based on a lithium niobate crystal. The device comprises a laser device 1, a diaphragm 2, a circular adjustable attenuator 3, an optical reshaper 4, an equal-ratio optical splitter 5, a light intensity detector 6, a background light source 7, a lithium niobate chip 8, a transparent final motion chip horizontal movement platform 9, a focusing objective lens 10, a semi-transparent and semi-reflective mirror 11, a first-stage optical filter 12, a second-stage optical filter 13, a CCD camera 14 and a rigidity support 15. The real-time controllable micro-droplet jetting device is composed of a micro-droplet jetting optical path, a real-time observation optical path and a light intensity detection optical path, and the lithium niobate chip 8 and the transparent final motion chip horizontal movement platform 9 are core devices of the micro-droplet jetting device. Jetting of polarity droplets can be achieved through the simple device, and the jetting speed of the jetting device can be controlled. The technology can be used for mixing and separating of a trace of reagents and is of important significance in the fields such as biological and medical care, medicine diagnosis, food sanitation, environment monitoring and molecular biology.