40 results about "Second-harmonic generation" patented technology

The classical channel employs a transmit laser and classical modulator. The quantum channel employs a nonlinear medium and spontaneous parametric down conversion producing quantum entangled signal and idler photon pairs which are encoded. The classical and quantum channels are combined to define a propagated hybrid signal. The receiver splits the hybrid signal on basis of wavelength into classical and quantum channels. The quantum receiver employs optical parametric amplification, supplied with energy from a second harmonic generation device synchronized to the classical carrier wavelength. A photodetector and extracts a quantum message from the quantum signal.

Systems and methods are disclosed for using second-harmonic generation of light to monitor the manufacturing process for changes that can affect the performance or yield of produced devices and / or determining critical dimensions of the produced device. A sample characterization system directs light onto a sample to produce second harmonic generation (SHG) signals and a detector generates detected SHG signals in response to receiving second harmonic generation (SHG) signals from the sample. A hardware processor receives detected SHG signals and determines a geometric feature of the sample or a variation in the geometric feature of the sample based on the detected SHG signals.

The metrology system may include an illumination source for generating an illumination beam and an illumination subsystem for directing the illumination beam toward a sample having an inversion-symmetric substrate and one or more films disposed on the inversion-symmetric substrate. The system may further include a filter configured to block wavelengths of the illumination beam and pass wavelengths associated with second harmonics of the illumination beam, and a detector for capturing second harmonic generation (SHG) light. The system may further include a controller for receiving metrology data from the detector associated with the SHG light from an interface between the inversion-symmetric substrate and the one or more films, and generating one or more metrology measurements associated with the one or more films based on the metrology data.

The present invention relates to a device for spectroscopic measurements, in particular X-ray diffraction (XRD), tem- perature-resolved second harmonic generation (TR-SHG) or infrared (IR) measurements, which prevents the formation of condensation (dew) or ice (frost) when carrying out spectroscopic measurements in sub-ambient temperature conditions and to a method of spectro- scopic measurements with said device.

To provide an SHG (second harmonic generation) capable of emitting a laser beam having a wave length shorter than that of 215nm.SOLUTION: The SHG device 1 has an optical crystal layer made of a nonlinear optical crystal, a lower DBR layer disposed on the lower surface of the optical crystal layer, and an upper DBR layer disposed on the upper surface of the optical crystal layer. The lower DBR layer has a double structure of a lower first 1DBR layer disposed on the optical crystalline layer side and a lower second 1DBR layer disposed under the lower first 2DBR layer. The second harmonic reflectivity of the lower 1DBR layer is higher than the second harmonic reflectivity of the lower 2DBR layer. The lower 2DBR layer has a reflectivity for the fundamental wave higher than that of the lower 1DBR layer. The second harmonic generated in the optical crystal layer is emitted through the upper DBR layer.SELECTED DRAWING: Figure 1

Various approaches can be used to interrogate a surface such as a surface of a layered semiconductor structure on a semiconductor wafer. Certain approaches employ Second Harmonic Generation while other utilize four wave-mixing or multi-wave mixing. Corona discharge may be applied to the sample to provide additional information. Some approaches involve determining current flow from a sample illuminated with radiation.

The invention relates to the technical field of lasers, in particular to a multi-wavelength output nanosecond laser. The laser comprises a pumping source, a pumping coupling device, a pumping end mirror, a gain crystal, a Q-switching device, a turning mirror, a frequency tripling crystal, a frequency doubling crystal and a tail end mirror. A pumping source, a pumping coupling device, a pumping end mirror, a gain crystal, a Q-switching device and a turning mirror are sequentially arranged in the light emitting direction of the pumping source. A turning mirror, a frequency tripling crystal, a frequency doubling crystal and a tail end mirror are sequentially arranged along the reflection direction of the turning mirror; the tail end mirror is a plane mirror, the end face, facing the frequency doubling crystal, of the tail end mirror is plated with a fundamental frequency light partial reflection film and a frequency doubling light high reflection film, and the transmittance of the fundamental frequency light partial reflection film is 2%-98%. The multi-wavelength output nanosecond laser provided by the invention can synchronously output multi-wavelength nanosecond laser with adjustable power pulse width by controlling the transmittance of the film layer of the output lens at the tail end.

A metrology system may include an illumination source to generate an illumination beam and an illumination sub-system to direct the illumination beam to a sample with an inversion-symmetric substrate and one or more films disposed on the inversion-symmetric substrate. The system may further include a filter configured to block a wavelength of the illumination beam and pass a wavelength associated with a second harmonic of the illumination beam and a detector to capture second harmonic generation (SHG) light. The system may further include a controller to receive metrology data from the detector associated with the SHG light from with an interface between the inversion-symmetric substrate and the one or more films and generate one or more metrology measurements associated with the one or more films based on the metrology data.

A second harmonic generation element includes a substrate, a first multilayer film reflecting mirror, a second harmonic generation layer, and a second multilayer film reflecting mirror. The first multilayer film reflecting mirror is formed on the substrate. The second harmonic generation layer is disposed on the first multilayer film reflecting mirror. The second harmonic generation layer is made of a SrB4O7 crystal that receives a fundamental wave with a predetermined wavelength and emits a second harmonic wave with a wavelength in an ultraviolet region. The second multilayer film reflecting mirror is formed on the second harmonic generation layer. The second multilayer film reflecting mirror constitutes a resonator with the first multilayer film reflecting mirror.

To overcome disadvantages when employing second harmonic generation (SHG), as established technique for semiconductor manufacture and measurement.SOLUTION: Second Harmonic Generation (SHG) can be used to interrogate a surface of a sample such as a layered semiconductor structure. The SHG based sample interrogation systems may simultaneously collect different polarization components of the SHG signal at a time to provide different types of information. SHG imaging systems 10000 can provide SHG images or maps of the distribution of SHG signals over a larger area of a sample 4120. Some such SHG imaging systems employ multiple beams and multiple detectors to capture SHG signals over an area of the sample. Some SHG imaging systems employ imaging optics 10114 to image the sample onto a detector array 10116 to form SHG image.SELECTED DRAWING: Figure 23

An inspection system may perform an inspection recipe by receiving reference SHG images of a reference structure based on a scan of the reference structure with an illumination beam and collecting second harmonic generation (SHG) light in response to the illumination beam, where the reference structure includes a multilayer structure including one or more inversion-symmetric materials. The system may further receive test SHG images of a test structure based on a scan of the test structure by illuminating the test structure with the illumination beam and collecting the SHG light in response to the illumination beam, where the test structure and the reference structure have a common design. The system may further identify defects in the test structure by comparing the test and reference SHG images.

Apparatus is described for performing simultaneous corona deposition and surface electric field induced second harmonic (EFISH) measurements. Example designs include systems including corona guns having a focus tube for deposition of corona charge with windows therein for passage of a laser beam incident on and reflected from a sample surface. Various designs may also employ masks proximal the distal end of the focusing tube and / or proximal the sample surface. In some implementations, the apparatus is used to make ungrounded and therefore non-invasive measurements, for example, on dielectric on semiconductor such as, e.g., interface state density (Dit), flatband voltage (Vfb) and / or lifetime measurements.

An optical surface analysis device (1) allows for the advantageous measurement, at the same location on a sample surface, of a nonlinear second harmonic generation (SHG) signal and a linear absorption signal in reflectivity, and their correlation to obtain information about the sample surface microstructure. The optical device was designed to integrate nonlinear reflectometry for SHG signal detection, visible reflection-absorption spectroscopy (Vis-RAS), and a visual control device for the sample surface using bright-field microscopy (CF), while maintaining the device's compact size. Abstract figure: Figure 1

The invention relates to a 2-halogen ethane sulfonate second-order nonlinear optical crystal and preparation and application thereof, the chemical formula of the crystal material is Na [SO3 (CH2) 2X] (H2O), X = Cl or Br, the crystalline material belongs to a monoclinic system, the space group is Pc, and the cell parameters are alpha = gamma = 90 degrees, beta = 91.86-92.86 degrees, and Z = 2. The powder frequency doubling effects of the non-linear optical crystals Na [SO3 (CH2) 2Cl] (H2O) and Na [SO3 (CH2) 2Br] (H2O) under 1064nm laser irradiation are respectively 0.6 and 0.8 times of that of KH2PO4 (KDP), the powder frequency doubling intensities of the non-linear optical crystals Na [SO3 (CH2) 2Cl] (H2O) under 532nm laser irradiation are respectively 0.1 and 0.2 times of that of beta-BaB2O4 (BBO) crystals, and phase matching can be realized. In addition, Na [SO3 (CH2) 2Cl] (H2O) and Na [SO3 (CH2) 2Br] (H2O) have moderate birefringence (0.09 at-546 nm and 0.106 at-546 nm) and short ultraviolet absorption cut-off edges (190 nm and 208 nm), and millimeter-level single crystals are easy to grow. The wavelength range of the coherent light source can be expanded through optical frequency conversion technologies such as second harmonic generation and optical parametric amplification, and important application value is shown in the fields such as laser frequency conversion and photoelectric information storage.

The utility model discloses an ultraviolet optical fiber optical parametric oscillator based on tunable picosecond green light. The ultraviolet optical fiber optical parametric oscillator comprises a high-power wavelength and repetition frequency adjustable 1 [mu] m laser system, a high-power second harmonic generation device and an optical fiber optical parametric oscillator, the high-power wavelength and repetition frequency adjustable 1 [mu] m laser system comprises a mode-locked fiber laser, a pulse stretcher, an adjustable fiber filter, a fiber pre-amplifier, a fiber collimator and a solid amplifier. According to the utility model, the wavelength of ultraviolet laser can be flexibly adjusted; through a narrow-band filtering technology, the generation efficiency of the ultraviolet laser is improved; an optical parametric oscillator based on a nonlinear optical fiber is designed, a more compact resonant cavity structure is realized, the influence of a heat effect on system efficiency and stability is inhibited, and ultraviolet laser with an excellent light spot mode can be output; the dispersion parameter of the nonlinear optical fiber can be regulated and controlled, so that the phase matching condition of four-wave mixing is optimized, and the efficiency and wavelength tuning range of ultraviolet laser are further improved.

The invention discloses a method for constructing a Bloch surface wave structure based on mode matching enhanced second harmonics, and the method comprises the steps: S1, constructing a multi-period one-dimensional photonic crystal on a substrate, enabling the multi-period one-dimensional photonic crystal to support a surface wave mode at the same time in a 750-840 nm fundamental frequency band and a 380-460 nm second harmonic wave band, and achieving the intersection point of a dispersion curve in a momentum space, therefore, the propagation phase speed matching of the fundamental frequency light and the second harmonic is achieved. S2, a double-grating coupling structure is etched on the surface of the photonic crystal, the double-grating coupling structure comprises an excitation grating used for exciting fundamental frequency surface waves and an emission grating used for exporting second harmonics, and efficient energy input and output are achieved; and S3, integrating a 3R-MoS2 nonlinear material with a nanoscale thickness between the gratings, and remarkably enhancing the frequency conversion efficiency by utilizing the interaction between the high nonlinear polarizability and the local field intensity of the 3R-MoS2 nonlinear material. According to the invention, low-loss and high-efficiency second harmonic generation is realized through an all-dielectric structure.

This invention provides a composite structure for enhanced second harmonic generation, its fabrication method, and its application. The composite structure includes a substrate and a GaN-based structure and an AlScN layer sequentially disposed along a direction away from the substrate; the GaN-based structure includes an n-type GaN layer, and the AlScN layer is heterojunction-coupled to the n-type GaN layer; furthermore, the AlScN layer contains a material with the chemical formula Al. 1‑ x Sc x The N and x values ​​are 0.1~0.43, and the crystal structure is hexagonal wurtzite with a preferred c-axis orientation. The thickness of the AlScN layer is greater than 60 nm. The composite structure provided by this invention can achieve second harmonic enhancement in the 1200nm~1300nm band, solving the problem of insufficient second harmonic intensity in pure GaN bulk materials or single epitaxial GaN-based structures in the prior art.

The invention relates to the technical field of lasers, in particular to a nanosecond ultraviolet solid laser in a Hermite-Gaussian mode. The laser comprises a pumping source, a pumping coupling device, a pumping end mirror, a gain crystal, a Q-switched crystal, a turning mirror, a frequency tripling crystal, a frequency doubling crystal and a tail end mirror. The pumping source, the pumping coupling device, the pumping end mirror, the gain crystal, the Q-switched crystal and the turning mirror are sequentially arranged along the light emitting direction of the pumping source; a frequency tripling crystal, a frequency doubling crystal and a tail end mirror are sequentially arranged along the refraction direction of the turning mirror; the pumping coupling device is internally provided with a lens group which is plated with a pumping light high-transmittance film, and the coupling ratio is 1: 1 to 1: 10; and the radius of curvature of the pumping end mirror is-5000 to 5000 mm. By adjusting the coupling proportion of a middle lens group of the pumping coupling device and the curvature radius of a pumping end mirror, the matching mode of the pumping light and the fundamental frequency light can be adjusted, so that the ultraviolet laser in a high-order Hermitian-Gaussian mode is obtained.

The invention belongs to the field of nonlinear optical materials, and provides a preparation method and application of a nonlinear optical crystal based on 4-nitrobenzene alanine, and the nonlinear optical crystal is prepared by combining organic 4-nitro-D-phenylalanine cations with inorganic nitrate anions according to a specific proportion. According to the method, two optical crystals with non-centrosymmetric structures, namely 4-nitro-D-phenylalanine nitrate and 4-nitro-D-phenylalanine monohydrate, are obtained, the two nonlinear optical crystals both have excellent second harmonic generation performance which is 3.4 * KDP and 2.8 * KDP respectively, and due to a three-dimensional hydrogen bond network of the 4-nitro-D-phenylalanine nitrate, the 4-nitro-D-phenylalanine monohydrate has excellent second harmonic generation performance. The material shows excellent thermal stability, solves the problems of poor stability of an organic material, limited nonlinear coefficient and structural adjustability of an inorganic material and self-offset of frequency doubling signals caused by a central symmetry structure, and is suitable for frequency conversion devices, photoelectric signal modulation devices, quantum information processing devices and the like in all-solid-state lasers.

The application discloses a kind of based on double topological corner state second harmonic generation device and method, with same energy band structure but opposite inner layer topological photonic crystal and outer layer topological photonic crystal of bulk polarization composition for second harmonic generation topological photonic crystal structure.It is equilateral triangle in the region boundary of inner layer topological photonic crystal and outer layer topological photonic crystal, under nearest neighbor interaction and long-range interaction, high Q value I type topological corner state and II type topological corner state appear near the three vertices of equilateral triangle region, and make the intrinsic frequency of II type topological corner state be twice the intrinsic frequency of I type corner state.When the light power density irradiated on inner layer topological photonic crystal reaches and exceeds second harmonic generation threshold, nonlinear interaction will occur between I type corner state and II type corner state, so that the second harmonic mode corresponding to II type corner state is excited out, realizes high-efficiency second harmonic generation, and is topologically protected, has certain anti-interference to defect.

A process for the generation of a second harmonic radiation from a fundamental radiation, comprising the following operating steps: providing one or more nonlinear crystals (C) that satisfy the condition of second harmonic generation (SHG) through noncritical phase matching; providing an optical phase actuator (A), positioned upstream or downstream of said nonlinear crystal (C) with respect to the main optical axis (O) of the nonlinear crystal, a step of varying one or more of said parameters of the optical actuator (A) over time by controlling the temperature of the optical actuator (A) itself, or by applying electric or magnetic fields to said optical actuator (A), determining said parameters of the optical actuator (A) for which said measured power is maximum with respect to the power measured during said plurality of measurements performed.

The invention discloses a method and a device for regulating and controlling a high-order Poincare spherical beam, and provides a method for effectively regulating and controlling the high-order Poincare spherical beam with complex vector polarization distribution in multiple dimensions such as angular momentum, light intensity distribution, polarization state and the like by using a nonlinear optical crystal based on a nonlinear effect of second harmonic. And different phase matching conditions in the second harmonic generation process are set, so that the regulation and control results of the second harmonic of the high-order Poincare spherical beam are enriched. According to the method and the device, a good effect is achieved during nonlinear regulation and control of the high-order Poincare spherical beam, the structure is simple, the cost is low, regulation and control of multi-dimensional optical properties are achieved, and the method and the device are suitable for design of optical nonlinear polarization imaging elements.

The present application discloses a device for detecting volatile organic compounds comprising modules suitable for photoionization detection operating under atmospheric pressure. The device comprises a laser with wavelength tuning capabilities, and applies a two-step non-linear wavelength conversion process of Second Harmonic Generation and Third Harmonic Generation. The device is provided with an array of dielectric nanomembranes that are suitable to induce Third Harmonic Generation (THG) of the light. Gas sensing with the present device provides real-time selective detection of volatile organic compounds.

The invention relates to an application of second harmonic imaging in collagen detection. The application comprises the following steps: irradiating a sample containing collagen by utilizing near-infrared laser, collecting a second harmonic signal generated by the collagen in the sample, and carrying out imaging and quantitative analysis on collagenous fibers based on the second harmonic signal. A collagen detection scheme based on secondary harmonic imaging is developed, samples are not damaged, low photobleaching and phototoxicity are achieved, the resolution ratio is high, dynamic ultra-long space-time in-vivo imaging can be achieved, a scheme for detecting myocardial fibrosis is further developed, in-situ and in-vivo space-time dynamic imaging on myocardial fibrosis is achieved for the first time, and the method has the advantages of being high in sensitivity, high in sensitivity and the like. An important tool is provided for accurate detection of myocardial fibrosis, and the method can be effectively applied to construction of products for detecting myocardial fibrosis, screening / evaluation of therapeutic drugs and the like.

The application discloses an electron transfer type photochromic crystal material and a preparation method and application thereof. The electron transfer type photochromic crystal material [(CBbpy)Zn3(TBC)2(H2O)]·NO3 is prepared by taking 1-(4-cyanobenzyl)-4,4-bipyridinium salt as a single viologen ligand and taking benzenetricarboxylic acid as a strong electron donor. The crystal has a large second harmonic generation effect, and also has a very large nonlinear optical switching ratio, and the switching ratio is up to about 25 times, which is three times of the highest nonlinear optical switchable ratio record (8 times) of the electron transfer type switch material. Therefore, the electron transfer type photochromic crystal material can be applied as a nonlinear optical switch material.

The application discloses a kind of phase perfect matching high-efficiency second harmonic generation efficiency nonlinear optical structure, including fundamental wave resonant structure, nonlinear optical layer, second harmonic reflection structure and substrate;Fundamental wave resonant structure is used to generate electromagnetic field local enhancement at incident fundamental wavelength, and phase matching condition is realized by optimizing electric field phase distribution;Nonlinear optical layer is used for frequency conversion of fundamental wave to second harmonic, and harmonic radiation capacity and phase control are regulated;Second harmonic reflection structure is used to control the coupling-out of second harmonic;Rotating nonlinear optical layer can adjust the phase characteristics of radiated second harmonic, to realize the phase perfect matching of harmonic field;The phase perfect matching high-efficiency second harmonic generation efficiency nonlinear optical structure realizes the accurate control of phase matching condition by reasonable optical thin film stack and phase matching technology, ensures the efficient coupling-out and utilization of second harmonic.

The invention discloses a method and a system for non-destructively detecting the polarity of an AlN (aluminum nitride) crystal. According to the method, detection is realized based on the phase matching relationship between the polarity of the AlN crystal and a second harmonic (SHG). The AlN crystal is of a non-centrosymmetric wurtzite structure, an SHG signal generated by excitation of an Al polar surface and an N polar surface of the AlN crystal along a c axis has an inherent phase difference with a period of pi, accurate discrimination of the polarity of the AlN crystal is realized based on the phase matching characteristic of the SHG signal, and no physical damage exists in the detection process. When the method is implemented, pulse laser normally enters the surface of the AlN single crystal to be measured, and an SHG signal of the AlN single crystal to be measured is collected and measured; comparing the phase of the to-be-measured signal with the phase of the known Al polar surface standard sample, and if the two phases are consistent, determining that the to-be-measured signal is an Al polar surface; and if the phase difference between the two is 180 degrees (pi), the polar plane is an N polar plane. The method is completely lossless, simple and convenient to operate and high in detection speed, can be used for polarity discrimination of the AlN single crystal and the substrate slice, and is suitable for industrial production detection of an aluminum nitride-based semiconductor material.

The application provides a method for enhancing second harmonic generation based on a non-linear energy transfer mechanism, obtaining a heterojunction composed of a donor two-dimensional material A and an acceptor two-dimensional material B, and then exciting by a two-photon pumping light source to induce non-linear energy transfer, thereby enhancing the second harmonic generation of the acceptor two-dimensional material B; in the heterojunction, the donor two-dimensional material A is (LA)2(A) n‑1 Pb n I 3n+1 ; wherein LA is a C3-C6 alkylammonium ion or a phenylammonium ion; A is a C1-C2 alkylammonium ion or a formamidate ion; n is 1-4; and the acceptor two-dimensional material B includes at least one of MoS2, MoSe2, WSe2 and h-BN. The application can effectively enhance the SHG of the acceptor material.

The application relates to a 2-methyl imidazole germanium-based iodide second-order nonlinear optical crystal and preparation and application thereof. The chemical formula of the crystal material is (2-C4N2H7)GeI3, wherein 2 represents a substitution position of a methyl group on an imidazole ring, namely 2-methyl imidazole. The crystal material belongs to an orthorhombic system, a space group is Pna21, cell parameters are a=13.82~14.02 Å, b=9.47~9.67 Å, c=8.36~8.56 Å, alpha=beta=gamma=90 DEG, and Z=4. The powder frequency doubling effect of the nonlinear optical crystal (2-C4N2H7)GeI3 of the application under 1200 nm laser irradiation is about 5.8 times that of KH2PO4 (KDP), and phase matching can be realized. In addition, (2-C4N2H7)GeI3 has a large birefringence (0.38 @ 546 nm) and a large optical band gap (an absorption cutoff edge is about 420 nm, and an optical band gap size is 2.95 eV), and a millimeter-level single crystal is easy to grow. It can expand the wavelength range of a coherent light source through optical frequency conversion technologies such as second harmonic generation and optical parametric amplification, and exhibits important application values in the fields of laser frequency conversion and photoelectric information storage.

Systems and methods for measuring electron density within a plasma are disclosed herein. An example system includes a laser source configured to emit a light beam, a first second harmonic generation (SHG) component configured to receive the light beam and generate a first harmonic light beam with a first polarization, and a plasma chamber containing a plasma, which the light beam and the first harmonic light beam pass through. The example system further includes a second SHG component configured to receive the light beam after passing through the plasma and generate a second harmonic light beam that has a second polarization. The example system further includes a heterodyne detection component configured to detect an interference pattern of the first harmonic light beam combined with the second harmonic light beam, and data processing circuitry configured to determine an electron density of the plasma based on the interference pattern.