81 results about "Second-harmonic generation" patented technology

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 and in some cases may utilize pump and probe radiation. Other approaches involve determining current flow from a sample illuminated with radiation. Decay constants can be measured to provide information regarding the sample. Additionally, electric and / or magnetic field biases can be applied to the sample to provide additional information.

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.

The invention relates to the technical field of lasers, and discloses a laser wavelength conversion device. Comprises: a polarizing lens; the half-wave plate is arranged on the incident light path of the polarized lens and connected with the electric control system, and the electric control system is used for controlling the half-wave plate to transversely move into the light path or move out of the light path or controlling the angle of the half-wave plate; the frequency doubling light path is communicated with the transmission light path or the reflection light path of the polarized lens; the fundamental frequency light serves as an incident light beam, and when the electric control system controls the half-wave plate not to transversely move into the light path, the fundamental frequency light enters the polarization lens in a vertical line polarization state and is reflected into the first frequency doubling light path, and frequency doubling light with the corresponding wavelength is output; when the electric control system controls the half-wave plate to transversely move into the light path, the polarization state of the fundamental frequency light is changed, the fundamental frequency light enters the polarization lens in a horizontal line polarization state and is transmitted into the next-stage light path, and if a subsequent half-wave plate and the polarization lens are arranged in the next-stage light path, the electric control system further controls the subsequent half-wave plate to transversely move into the light path or adjusts the angle. And outputting the frequency-doubled light with the corresponding wavelength.

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.

Methods and apparatus for obtaining 3D imaging of tissue involve scanning a focused laser beam in xz planes to obtain a set of xz plane images spaced apart in a y direction. The xz plane images are processed to correct distortions and motions and combined to provide 3D image data. Surface flatting is optionally performed. Imaging may be performed using a femtosecond (fs) laser beam. Different components of light returning from the tissue may be detected and processed to yield plural co-registered images using different imaging modalities, for example, reflective confocal microscopy (RCM), two photon fluorescence (TPF) and second harmonic generation (SHG).

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.

A measurement device includes a light source configured to emit a fundamental wave that is a femtosecond pulsed laser beam, a second harmonic generator configured to convert a portion of the fundamental wave into a first-second harmonic, a birefringent crystal configured to split an angle for the first-second harmonic, a wavelength selection element configured to block the fundamental wave and transmit therethrough the first-second harmonic and a second-second harmonic, a polarizer configured to polarize the first-second harmonic and the second-second harmonic to approximately same polarizations, and an image detector.

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.

In one embodiment, there is provided a method for discovering a two-dimensional (2D) material capable of second harmonic generation (SHG). The method includes training, by a training module, an SHG material discovery module based, at least in part, on one or more training machine learning (ML) descriptors. The method further includes predicting, by the trained SHG material discovery module, an SHG for a candidate material based, at least in part, on a received material descriptor. The received material descriptor is associated with the candidate material.

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.

Methods and systems for improving the detection of defects of interest and the measurement of structures buried within complex three-dimensional semiconductor structures are described herein. A transmission focus scanning optical microscope (TSOM) using a non-linear second harmonic generation (SHG) optical signal emitted from a sample provides interfacial selective sensitivity for metrology and inspection of advanced semiconductor structures. The TSOM / SHG system includes a spectral filter to pass collected light at a wavelength corresponding to the SHG emission. In some embodiments, the TSOM / SHG system includes an ultrafast pulsed laser source that emits ultraviolet rays to near infrared wavelengths to efficiently induce the SHG at the surface interface. The halving of the wavelength inherent to the SHG results in a doubling of the illumination wavelength without loss of resolution. In another aspect, the TSOM / SHG measurement system includes an exogenous illumination source, an external electric field source, or both to induce a DC electric field at one or more interfaces of the structure under illumination, thereby enhancing SHG emission.

The present invention provides a laser driving device and a method for obtaining a uniform light field. The laser driving device is a high laser driving device for laser fusion level that obtains a uniform light field based on narrowband low-spatial-coherence light. The narrowband low-spatial-coherence light serves as the seed source of the laser driving device, the amplification and transmission unit amplifies the seed source, the frequency conversion unit realizes laser frequency conversion, and the focusing component is used for laser focusing and uniform illumination. The present invention improves the uniformity of the output light field of the laser driving device, solves the problem of low second harmonic generation efficiency caused by the wide spectral band technical solution and reduces the problem of optical element damage caused by self-focusing, breaks through the energy limitation caused by the limited load of ultraviolet elements, improves the overall output energy of the laser driving device, and further improves the overall efficiency of the laser device.

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.

The embodiment of the invention provides a method for generating second harmonics of patterned graphene. The method comprises the following steps: forming a graphene thin layer on a substrate with a groove structure; and using ultrafast laser pulses to excite graphene second harmonics at the suspended edge at the trench structure region of the substrate and generate patterned second harmonics. According to the patterned graphene second harmonic generation method provided by the embodiment of the invention, the graphene on the suspended edge of the groove structure is excited through the ultrafast laser pulse, so that patterned second harmonic generation can be efficiently and accurately realized. The embodiment of the invention also provides a graphene structure.

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.

The invention relates to an ultraviolet nonlinear optical material CdF (C6H4NO2) (H2O) as well as a preparation method and application thereof. The crystal structure of the ultraviolet nonlinear optical material CdF (C6H4NO2) (H2O) belongs to a monoclinic system, the space group is P21, the cell parameters are as follows: # imgabs0 # imgabs1 # alpha = gamma = 90 degrees, beta = 114.506 (4) degrees, and the cell volume # imgabs2 # in the ultraviolet nonlinear optical material, Cd is coordinated with N of one (C6H4NO2)-, O of another (C6H4NO2)-, O of a water molecule and three F-to form a twisted [CdF3NO2] octahedron; the [CdF3NO2] octahedrons with two orientations are alternately arranged along a b axis to form a zigzag one-dimensional chain; the one-dimensional chains are mutually connected through (C6H4NO2) <-> to form a Wollan truss bridge-like structure. The unique structure promotes the optimal arrangement of [CdF3NO2] octahedron and (C6H4NO2)-in crystal lattices, so that the ultraviolet nonlinear optical material simultaneously has the characteristics of strong second harmonic generation (3.2 times of KDP), large birefringence (0.26 at546 nm) and deep ultraviolet transparency (Eg = 4.41 eV), and solves the long-standing challenges in the quantum optical technology.