58 results about "Second-harmonic generation" patented technology

The invention provides a novel environment-friendly insulating gas surface flashover characteristic evaluation method based on surface charge on-line measurement, which comprises an electric field measurement system based on an electric field induced second harmonic effect (EFISH), a coupling high-voltage surface flashover experiment system, and an evolutionary process of an electric field in a process of applying high voltage to surface flashover, the evolutionary process of charge distribution is obtained based on the electrostatic field source relation, the starting moment of surface flashover is determined by measuring sound, light and electromagnetic signals in the surface flashover process, and the starting area of the surface flashover is observed through a high-speed camera; and associating the relationship between the charge and the surface flashover, and quantitatively explaining the induction effect of the charge on the flashover.

The invention discloses an organic all-dielectric nonlinear metasurface based on a quasi-continuous domain bound state, the organic all-dielectric nonlinear metasurface is formed by periodically arranging a plurality of unit cell units, and each unit cell unit comprises a substrate layer, an intermediate dielectric layer and a resonant unit structure layer which are sequentially arranged from bottom to top, the cross section of the resonance unit structure layer is in an L shape, the L shape is a square surface without a rectangular angle, and the intermediate dielectric layer is made of an organic nonlinear material. By designing the organic all-dielectric nonlinear metasurface structure, the asymmetry degree of the resonance unit structure is changed, perfect absorption of fundamental frequency light and local enhancement of an electric field are achieved, the second harmonic generation efficiency is improved, and the problems that an existing metal nonlinear metasurface is low in damage threshold and low in second-order nonlinear conversion efficiency are solved.

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.

The invention discloses a broadband nonlinear frequency converter which comprises a silicon dioxide coating layer, an x-cut lithium niobate film layer, a silicon dioxide buffer layer and a silicon substrate layer from top to bottom, the x-cut lithium niobate film layer is provided with a weak bending ridge waveguide, and the bending angle of the weak bending ridge waveguide is not larger than 5 degrees. According to the invention, birefringence phase matching is realized on the lithium niobate film in a weak bending waveguide form, so that broadband second harmonic generation, birefringence phase matching wavelength and matching angle correlation are realized, and an included angle between a wave vector of transmitted fundamental frequency light and a crystal optical axis is continuously and slightly changed through the weak bending film, so that the broadband second harmonic generation is realized. Therefore, birefringence phase matching of different wavelengths can be realized at different matching angles, and the purpose of broadband matching is achieved.

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 discloses a gas chamber temperature control method for a SERF inertial measurement device based on second harmonic generation. The method utilizes gas chamber optical depth information obtained by the SERF device's own detection system to perform feedback regulation on the laser heating power of the atomic gas chamber, thereby achieving real-time and stable control of the atomic density or temperature in the gas chamber. This avoids the magnetic field interference introduced by the use of thermal resistors as temperature sensors in existing solutions, thereby achieving truly non-magnetic, all-optical gas chamber heating and its control system, and helping to improve the sensitivity of the SERF inertial measurement device.

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.

The application belongs to the field of nonlinear optical materials, and relates to a kind of ultraviolet nonlinear optical crystal material and its preparation method and application.The crystal chemical formula of the ultraviolet nonlinear optical crystal material is Zn (C5H4NO) 2, C5H4NO represents 4-hydroxy pyridine, 4-hydroxy pyridine is combined with Zn 2+ Form [ZnN2O2] tetrahedron by coordination bond;The crystal belongs to the orthorhombic system, and the space group is Fdd2.The band gap of the ultraviolet nonlinear optical crystal material is 4.40eV, the second harmonic generation is as high as 13.6xKDP, the birefringence Δn at 532nm wavelength is 0.073, the birefringence Δn at 1064nm wavelength is 0.074, and it shows photoluminescence characteristics, has phosphorescence with a lifetime of 558ms under the excitation light with a wavelength of 330-420nm, and blue afterglow with a naked eye visible and a duration of 5s.In addition, the ultraviolet nonlinear optical crystal material has strong water resistance, thermal stability and environmental stability, and has good application prospect in the field of nonlinear optical materials.

The invention relates to an integrated photonic device (100) configured for near-perfect second harmonic generation (SHG) at a resonant optical wavelength λ. The device includes a substrate (S), a first (101) and second (109) distributed Bragg reflector (DBR) made of alternating layers with different refractive indices (103, 105), and a monolayer of MoS2 (ML MoS2) as the nonlinear material sandwiched between identical insulating layers (102). The device utilizes a Fabry-Perot cavity configuration, enhancing the electric field at λ, ensuring maximum SHG efficiency. The phase matching condition is satisfied due to the sub-nm thickness of MoS2 layer of 0.62 nm. The device is an SHG device with an input at 1550 nm and an output at 775 nm, with SHG conversion efficiencies higher than 99%. Ultra high nonlinear susceptibility of MoS2 also optimizes SHG performance, and the device is therefore very efficient for photonic applications.

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

The invention relates to a pulse measurement method based on two-photon absorption, and the method comprises the following steps: S1, selecting perovskite as a medium, and placing the medium on a sample stage of a Michelson interferometer; s2, the light source emits an ultrashort laser pulse to be measured and divides the ultrashort laser pulse into two paths of pulses, one path of pulse passes through the adjustable delay line and then is combined with the other path of pulse in perovskite, and a two-photon absorption signal is generated; and S3, obtaining a two-photon absorption interference autocorrelation curve IAC experiment through the two paths of pulses and the two-photon absorption signal, and reconstructing to obtain complete information of the to-be-measured ultrashort laser pulse by combining the spectral intensity of the to-be-measured ultrashort laser pulse. According to the invention, multi-photon absorption response is taken as a core detection mechanism, so that the technical limitation of traditional non-linear effects depending on second harmonic generation and the like is effectively broken through, the problem that materials such as perovskite and the like do not have second harmonic so that pulse measurement cannot be realized is solved, and measurement of higher sensitivity and wider wave band of ultrafast light pulses is realized.

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.

The present invention relates to a molybdenum strontium peroxide second-order nonlinear optical crystal and its preparation and application. The chemical formula of the crystal material is SrMo2O3(O2)4(H2O)2·3H2O, the molecular weight is 545.58, it belongs to the tetragonal crystal system, its space group is , the unit cell parameters are α=β=γ=90°, Z=8, and the unit cell volume is . The molybdenum strontium peroxide crystal material of the present invention has excellent optical properties. Under 1064nm laser irradiation, the powder frequency harmonic intensity is about 3 times that of potassium dihydrogen phosphate crystal, and phase matching can be achieved. The crystal material is not only easy to grow, but also can effectively expand the wavelength range of coherent light sources through optical frequency conversion technologies such as second harmonic generation and optical parametric amplification. In the fields of laser lithography, laser processing, medical diagnosis and treatment, this crystal material shows important application prospects.

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.

The present invention discloses a micro-area scanning imaging device and measurement method, comprising a laser, a dual-axis scanning galvanometer SM that focuses the laser light on a sample S, a cubic beam splitter CB, and a microscope objective lens OB. The cubic beam splitter CB splits the signal light reflected from the sample S after the laser is irradiated onto the sample S and transmits it to a sample signal detector SD. A plate-shaped beam splitter PB is provided between the cubic beam splitter CB and the sample signal detector SD to further split the signal light to a laser detector PD. During the measurement process, a two-dimensional characteristic light signal map of the surface of the sample S is first obtained based on the sample signal detector SD. Then, a blank substrate is placed in the area to be measured, and a two-dimensional reflected light signal map of the substrate in the same area as the sample S is obtained based on the laser detector PD. The two-dimensional characteristic light signal map is normalized based on the two-dimensional reflected light signal map to obtain the normalized two-dimensional characteristic light signal map, and a two-dimensional spatial scanning map of the physical properties of the sample S is further drawn. The present invention is suitable for collecting signals such as fluorescence spectroscopy, Raman spectroscopy, and second harmonic generation. By performing two-dimensional laser scanning on the sample surface, high-resolution imaging of micro-areas of various materials is achieved.

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.

The present invention discloses an on-chip mid-infrared frequency-doubling polarization composite device and its implementation method. The present invention uses tellurene nanosheets to demonstrate significant second harmonic generation efficiency in an ultra-wideband region from near-infrared to mid-infrared. Furthermore, the intensity of the optical second harmonic signal reaches its highest intensity only when the incident light polarization direction is perpendicular to the a-axis of the tellurene nanosheet, and is extinguished when it is orthogonal, resulting in a high extinction ratio. The present invention exhibits excellent broadband mid-infrared second harmonic generation response, promising a solution to the difficulty in efficiently frequency-doubling mid-infrared light in on-chip integrated environments, opening up new avenues for the development of advanced photonic technologies. Based on the significant anisotropy of the tellurene nanosheet-optical second harmonic signal, the present invention is able to regulate the polarization of the emitted optical second harmonic signal, exhibiting versatility and ease of integration. The present invention is highly suitable for large-scale manufacturing and saves costs.

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 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 body. 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 invention, the wavelength of the 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 present invention relates to a second-order nonlinear optical crystal of formamidine thiosulfate, and its preparation and application. The crystal material has a chemical formula of [CH(NH2)2]2SO3S, a molecular weight of 203.27, belongs to the orthorhombic crystal system, has a space group of P212121, unit cell parameters of α=β=γ=90°, Z=4, and a unit cell volume of . The formamidine thiosulfate crystal material of the present invention has excellent optical properties. Under 1064nm laser irradiation, the powder frequency harmonic intensity is approximately twice that of potassium dihydrogen phosphate crystal, and phase matching can be achieved. In addition, the crystal material has a wide light transmission band, an ultraviolet absorption cutoff edge of 253nm, an optical band gap of 4.90eV, and is easy to grow. Optical frequency conversion technologies such as second harmonic generation and optical parametric amplification can be used to expand the wavelength range of coherent light sources. Therefore, the crystal material has important application value in fields such as laser frequency conversion and optoelectronic information storage.

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.