1101 results about "Nonlinear optical crystal" patented technology

A fiber-laser-based implementation of a Terahertz source through difference frequency generation (DFG) by nonlinear optical (NLO) crystals is compact, tunable and scalable. A pair of fiber lasers (Q-switched, CW or mode-locked) generate single-frequency outputs at frequencies ω1 and ω2. A fiber beam combiner combines the laser outputs and routes the combined output to a THz generator head where a nonlinear interaction process in the NLO crystal generates THz radiation.

A laser device which can be used as a light source for an exposure device, can be downsized, and is easy to maintain. A laser beam (LB6) emitted from a DFB (Distributed feedback) semiconductor laser, for example, and amplified by an optical fiber amplifier is passed through non-linear optical crystals (502, 503, 504) to be sequentially doubled in frequency to thereby generate an ultraviolet-region laser beam (LB5) consisting of an octuple wave. A GdYCOB, that is, Gd_xY_1−xCa₄O(BO₃)₃ crystal (0≦×≦1) is used for the non-linear optical crystal (503) for a double wave-to-quadruple wave conversion, and a KAB, that is, K₂Al₂B₄O₇ crystal for the non-linear optical crystal (504) for a quadruple wave-to-octuple wave conversion. The non-linear optical crystals (502-504) are all fine-tuned in phase match angle by temperature controllers (521-523) respectively.

A system for generating signals for Raman vibrational analysis, particularly for a CARS microscope or spectroscope of an external specimen, the system comprising a a laser source apt to emit at least one fundamental optical pulse in a first band of fundamental frequencies comprising at least one first (ω_f1) and one second (ω_f2) fundamental frequencies; a second-harmonic (SH) generating system comprising at least one nonlinear optical crystal for converting said at least one fundamental optical pulse into at least two second-harmonic optical pulses, i.e. a first second-harmonic pulse at a first second-harmonic frequency (ω_p) of the first fundamental frequency (ω_f1) and a second second-harmonic pulse at a second second-harmonic frequency (ω_s) of the second fundamental frequency (ω_f2), said second second-harmonic frequency being other than the first second-harmonic frequency, and a Raman vibrational analysis apparatus apt to receive said first and second second-harmonic pulses and direct them toward said specimen.

According to an embodiment, the SH system comprises two nonlinear optical crystals, each including a ferroelectric crystal with periodic space-modulation of the sign of the optical susceptibility.

In a different embodiment, the SH system comprises a ferroelectric crystal with aperiodic space-modulation of the sign of nonlinear optical susceptibility, with a period varying along the optical path of said at least one fundamental optical pulse, said crystal being apt to generate said first and second second-harmonic pulses.

A method for producing low-noise laser output at wavelengths ranging from IR through visible to UV in various operation modes from a monolithic microchip laser comprises schemes of (1) generating one or two fundamental beam(s) from light source(s) selected upon the desired wavelength(s), polarization(s), and other features related to the desired laser output; (2) intracavity beam combination/separation due to the walk-off effect in one or more birefringent crystal(s) transparent to the propagating lights and highly anisotropic; (3) wavelength conversion in one or more nonlinear optical crystal(s); (4) compact and efficient pump source(s); and (5) minimization of intracavity loss/noise. One resonator cavity supports only one fundamental beam, which eliminates the green problem. The gain media can be selected from an extensive group of materials including isotropic and naturally birefringent crystals, with polarization dependent or independent laser emissions. Laser devices constructed in accordance with the inventive method are demonstrated with various configurations.

A measurement system, comprising: a first light source that generates first light and irradiates an object with the first light, at least one of an intensity, a polarization state, and a wavelength being modulated with a first period in the first light; a second light source that generates second light, at least one of an intensity, a polarization state, and a wavelength being modulated with a second period in the second light; a first optical system that mixes light from the object based on the first light with the second light; a nonlinear optical crystal that generates third light from the mixed light by sum-frequency generation phenomenon, the third light having a frequency equivalent to a sum of a frequency of the light from the object based on the first light and a frequency of the second light; and a photodetector that measures an intensity of the third light.

In nonlinear optical crystal 183D, each step of wavelength conversion can be performed using another fundamental wave that is output from light output unit 161₂, without using the fundamental wave whose output level has been attenuated after going through wavelength conversion for several steps (wavelength conversion in nonlinear optical crystals 183A to 183C). Therefore, the wavelength conversion efficiency improves and the peak power of optical amplifiers 161₁ and 161₂ can be suppressed, which allows the wavelength of lights that are output from optical amplifiers 161₁ and 161₂ to be further narrowed.

An electromagnetic wave generator encompasses a first pump beam emitter (2) configured to emit a first pump beam (hv₁) having a wavelength larger than one micrometer; a second pump beam emitter (25) configured to emit a wavelength-tunable second pump beam (hv₂) having a wavelength larger than one micrometer, the wavelength of which is different from the wavelength of the first pump beam (hv₁); a nonlinear optical crystal (19) configured to generate an electromagnetic wave (hv₃) of a difference frequency between the first pump beam (hv₁) and second pump beam (hv₂); and an optical system (M₁, M₂, 18) configured to irradiate the first pump beam (hv₁) and second pump beam (hv₂) to the nonlinear optical crystal (19), by adjusting an external intersection angle between the first pump beam (hv₁) and second pump beam (hv₂) within 0.5° at the difference frequency of 1 THz. Here, a frequency-tunable terahertz electromagnetic wave (hv₃) is generated in the nonlinear optical crystal (19), by changing the frequency of the second pump beam (hv₂), being liked with the change of the external intersection angle.

Solid state lasers that use non-linear optical crystals to generate frequency tripled or quadrupled output in the ultraviolet have low lifetimes due to damage to the face of the non-linear crystal through which the ultraviolet signal exits. To prevent this damage, the tripling or quadrupling crystal is provided within a controlled environment that is maintained substantially free from contaminants such as silicon-bearing and organic compounds. The tripling or quadrupling crystal is enclosed within a tubular chamber with windows on the ends of the tube that provide optical access to the entrance and exit faces of the tripling or quadrupling crystal. All heating elements and alignment elements for the crystal are outside of the chamber. Because the crystal is stored within the hermetically sealed chamber, contaminants are not available within the environment of the crystal that could interact with the energetic photons of the ultraviolet output of the frequency multiplied solid state laser. The windows and walls of the chamber are preferably made of materials that can be cleaned effectively, such as sapphire or quartz for the windows and stainless steel for the walls and flanges of the chamber.

The invention relates to a time-resolved spectrum measurement instrument, in particular to a modularized femtosecond time-resolved transient absorption and fluorescence depletion two-in-one spectrometer. The modularized femtosecond time-resolved transient absorption and fluorescence depletion two-in-one spectrometer comprises an instrument optical flat, a pumping light path system and a probing light path system consisting of a plane mirror, a convex lens, a light diaphragm, a light filter, a time delay line, nonlinear optical crystals and a sample system, and also comprises a spectrum detection system. Since the spectrometer uses the optical flat as a bottom plate and various optical components, the modularization of the instrument is realized and the instrument can be moved on the whole; since a femtosecond time-resolved transient absorption spectrometer and a femtosecond time-resolved fluorescence depletion spectrometer are integrated into one, working personnel can conveniently conduct adjustment and the spectrometer can be widely popularized and used.

A compact optically-pumped solid-state laser designed for efficient nonlinear intracavity frequency conversion into desired wavelengths using periodically poled nonlinear crystals. These crystals contain dopants such as MgO or ZnO and/or have a specified degree of stoichiometry that ensures high reliability. The laser includes a solid-state gain media chip, such as Nd:YVO₄, which also provides polarization control of the laser; and a periodically poled nonlinear crystal chip such as PPMgOLN or PPZnOLT for efficient frequency doubling of the fundamental infrared laser beam into the visible wavelength range. The described designs are especially advantageous for obtaining low-cost green and blue laser sources.

A method for producing low-noise laser output at various wavelengths and/or in various operation modes in a monolithic microchip laser comprises schemes of generating two fundamental beams in separate cavities, precise intracavity beam combination based on the walk-off effect in birefringent crystal, and wavelength conversion in nonlinear optical crystals. The fundamental beams are produced from light sources selected upon the desired wavelengths, polarizations, and other features related to the laser output. Low-noise laser devices operated in SLM or with spectra of flat-top or desired bandwidths are constructed according to the method. High-volume fabrication is feasible. Apparatus of compact size and efficient frequency conversion is demonstrated with various configurations including those for generating low-noise 491 nm laser, as a replacement of Argon ion laser.

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.

The invention relates to a nonlinear optical crystal of a potassium borate chloride compound and a preparation method as well as application thereof. The chemical formula of the compound is K3B6O10Cl, and the molecular weight of the compound is 377.61. The crystal does not have a symmetric center and belongs to a trigonal system and a space group R3m, and cell parameters are as follows: a=10.0624(14), b=10.0624(14), c=8.8361(18), Z=3, and V=774.8 (2). The powder frequency-doubled effect reaches about 3 times of KDP(KH2PO4), the Mohs hardness is 4-5, and the light transmission waveband is 165nm-3460nm. A solid phase reaction method is used for synthesizing the compound, and a cosolvent method is used for growing the crystal. The crystal has the advantages of simple operation, low cost, large size, short growth cycle, few inclusion enclaves and larger mechanical hardness, and can be cut, polished, processed and saved easily. The crystal is used for generating twofold frequency or three-fold frequency or fourfold frequency or fivefold frequency harmonic light output for laser beams of which the wavelength is 1064nm.

The invention belongs to the technical field of crystal growth and relates to a growth method of organic nonlinear optical crystal. The growth method comprises the following steps of: firstly, drying a DAST (sulfur trifluoride) crystal growth raw material, dissolving the DAST crystal growth raw material in an absolute methanol solution to prepare a DAST methanol solution; then, heating and filtering the DAST methanol solution, and transferring the DAST methanol solution into a wild-mouth bottle; putting a polyfluortetraethylene plate in the wild-mouth bottle, and sealing the wild-mouth bottle; putting the wild-mouth bottle in a sealed water bath heating device to be thermally insulated, and cooling the wild-mouth bottle until the DAST crystal stops growing, taking out the crystal DAST crystal, namely, obtaining the DAST crystal with large surface area and thickness. The growth method is simple, the principle is scientific, the growth environmental is friendly, the cost is low, and the grown DAST crystal is large in geometric dimension, high in transmittance and convenient to be further processed and utilized.

At least one terahertz-wave generation device configured to generate a terahertz wave includes a polarization control unit configured to control a polarization direction of light from a light source, and a waveguide including a nonlinear optical crystal disposed such that the light having the polarization direction controlled by the polarization control unit is incident on the nonlinear optical crystal. The nonlinear optical crystal emits a terahertz wave upon the light being incident thereon. The polarization control unit is further configured to control an electric-field intensity of the light to be incident on the nonlinear optical crystal in a direction of a Z-axis of the nonlinear optical crystal.