102 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 relates to a formamidine thiosulfate second-order nonlinear optical crystal and preparation and application thereof, the chemical formula of the crystal material is [CH (NH2) 2] 2SO3S, the molecular weight is 203.27, the crystal material belongs to an orthorhombic crystal system, the space group is P212121, the unit cell parameter is # imgabs 0 # alpha = beta = gamma = 90 degrees, Z = 4, and the unit cell volume is # imgabs 1 #. Under 1064nm laser irradiation, the frequency doubling intensity of the powder is about two times that of monopotassium phosphate crystals, and phase matching can be realized. In addition, the crystal material has a wide light transmission wave band, the ultraviolet absorption cut-off edge is 253 nm, the optical band gap is 4.90 eV, and the crystal material is easy to grow. The wavelength range of the coherent light source can be expanded by using optical frequency conversion technologies such as second harmonic generation and optical parametric amplification. Therefore, the crystal material has important application value in the fields of laser frequency conversion, photoelectric information storage and the like.

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 discloses a non-linear optical structure with perfect phase matching and high second harmonic generation efficiency. The non-linear optical structure comprises a fundamental frequency wave resonance structure, a non-linear optical layer, a second harmonic reflection structure and a substrate, the fundamental frequency wave resonance structure is used for generating electromagnetic field local enhancement at an incident fundamental frequency wavelength and realizing a phase matching condition by optimizing electric field phase distribution; the nonlinear optical layer is used for frequency conversion from fundamental frequency waves to second harmonics and regulating and controlling harmonic radiation capability and phase regulation and control; the second harmonic reflection structure is used for controlling coupling-out of second harmonics; the rotary nonlinear optical layer can adjust the phase characteristic of the radiated second harmonic so as to realize perfect phase matching of a harmonic field; according to the nonlinear optical structure with perfect phase matching and high-efficiency second harmonic generation efficiency, accurate control of phase matching conditions is realized through reasonable optical film stacking and phase matching technologies, and high-efficiency coupling-out and utilization of second harmonics are ensured.

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.

Methods, devices and systems are described that enable identification of cancerous or pre-cancerous colon tissue. The described methods and systems rely on non-imaging. randomly sampled second harmonic generation (SHG) intensity measurements that are sufficient for differentiating between tumor and normal tissue. The disclosed methods and system further provide for angle-resolved SHG measurements associated with forward and backward scattered light that eliminate the need to obtain paired normal and cancer-suspicious measurements in each patient using the described techniques.

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.

The invention belongs to the field of nonlinear optical materials, and relates to an ultraviolet nonlinear optical crystal material and a preparation method and application thereof. The chemical formula of the ultraviolet nonlinear optical crystal material is Zn (C5H4NO) 2, C5H4NO represents 4-hydroxypyridine, and the 4-hydroxypyridine and Zn < 2 + > are combined through a coordinate bond to form a [ZnN2O2] tetrahedron; the crystal belongs to an orthorhombic system, and the space group is Fdd2. The band gap of the ultraviolet nonlinear optical crystal material is 4.40 eV, the second harmonic generation is as high as 13.6 * KDP, the birefringence delta n = 0.073 at the wavelength of 532 nm, the birefringence delta n = 0.074 at the wavelength of 1064 nm, and the ultraviolet nonlinear optical crystal material presents a photoluminescence characteristic, and has phosphorescence with the service life of 558 ms and blue afterglow visible to naked eyes and as long as 5 s under exciting light with the wavelength of 330-420 nm. In addition, the ultraviolet nonlinear optical crystal material has very strong water resistance, thermal stability and environmental stability, and has a good application prospect in the field of nonlinear optical materials.

Disclosed are methods and systems that make use of light scattering techniques, such as the use of a multiphoton laser-scanning microscope, to quantify the scattering directionality of second harmonic generation (SHG) from biopsy samples of cancer in order to predict efficacy of neoadjuvant chemotherapy.

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.

An optical amplification device (1a) comprises: an excitation light branching unit (12) that branches excitation light and generates first branched excitation light and second branched excitation light; a first optical amplifier (17) that amplifies the intensity of a first polarization signal light by an optical parametric amplification process using the first branched excitation light; a second optical amplifier (20) that amplifies the intensity of a second polarization signal light by an optical parametric amplification process; a first excitation light demultiplexing unit (18) that removes the first branched excitation light from the result of the optical parametric amplification process; a second excitation light demultiplexing unit (21) that removes the second branched excitation light from the result of the optical parametric amplification process using the second branched excitation light; a polarization multiplexing unit (22) that multiplexes the intensity-amplified first polarization signal light and the intensity-amplified second polarization signal light; and a filter (23) that transmits the result of multiplexing the intensity-amplified first polarization signal light and second polarization signal light. The line width of the excitation light is equal to or less than the full width at half maximum of a curve representing the generation efficiency of a second harmonic light in each second harmonic generation process of the first optical amplifier (17) and the second optical amplifier (20).

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 invention relates to a wavelength converter, an optical frequency comb generation device and a wavelength converter preparation method. The wavelength converter comprises a gain optical fiber and a nonlinear wavelength conversion material, the nonlinear wavelength conversion material is attached to the polishing plane of the gain fiber; and under the condition that the optical frequency comb with the initial central wavelength enters the gain fiber, generating an optical frequency comb with a preset central wavelength through the nonlinear wavelength conversion material. By introducing a nonlinear wavelength conversion material, the nonlinear wavelength conversion material is attached to a polished plane of a gain optical fiber, the second-order nonlinear effect of the gain optical fiber is remarkably enhanced, when an optical frequency comb with an initial central wavelength enters the gain optical fiber, the optical frequency comb with the initial central wavelength interacts with the nonlinear wavelength conversion material, and the optical frequency comb with the initial central wavelength interacts with the nonlinear wavelength conversion material. Through secondary harmonic generation, an optical frequency comb with a preset central wavelength is output, and efficient optical frequency comb generation near a 765nm wave band is realized.

The invention discloses an on-chip intermediate infrared frequency doubling polarization composite device and an implementation method thereof. According to the invention, the tellurene nanosheets are adopted to show huge second harmonic generation efficiency in an ultra-wideband region from near infrared to intermediate infrared; the intensity of the optical second harmonic signal is the strongest only when the polarization direction of the incident light is vertical to the a axis of the tellurene nanosheet, and the optical second harmonic signal is delustring when the incident light is orthogonal, so that the extinction ratio is very high; according to the invention, excellent broadband mid-infrared second harmonic generation response is shown, the problem that high-efficiency frequency multiplication conversion of mid-infrared band light is difficult to carry out in an on-chip integration environment is hopefully solved, and a new way is opened up for the development of an advanced photon technology; on the basis of obvious anisotropy of tellurium ene nanosheet-optical second harmonic signals, the polarization of the emergent optical second harmonic signals can be regulated and controlled, and the tellurium ene nanosheet-optical second harmonic signal modulator has the characteristics of multifunctionality and convenience in integration; the method is very suitable for large-scale manufacturing, and cost is saved.

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