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, inter alia, to a device (10) for analysing a material (101), comprising an excitation emission device (100) for generating at least one electromagnetic excitation beam (SA), particularly an excitation light beam, with at least one excitation wavelength, and further comprising a detection device (106) for detecting a reaction signal (SR), and a device (107) for analysing the material on the basis of the detected reaction signal (SR).

A wafer inspection apparatus includes: an objective lens on an optical path of first and second input beams; and an image sensor configured to generate an image of the wafer based on scattered light according to a nonlinear optical phenomenon based on the first and second input beams, wherein the first input beam passing through the objective lens is obliquely incident on the wafer at a first incident angle with respect to a vertical line that is normal to an upper surface of the wafer, the second input beam passing through the objective lens is incident on the wafer at a second incident angle oblique to the vertical line that is normal to the upper surface of the wafer, and the first and second incident angles are different from each other.

Herein are described data acquisition systems and methods applying such systems to determine three-dimensional (3D) diffusion tensors, and simultaneously, to perform 3D structure imaging. Example data acquisition systems can include computing systems in communication with modified light sheet microscopes that are configured for high-speed volumetric imaging to record 3D diffusion processes and high-resolution 3D structural imaging.

An optical resonance imaging system includes a light emitting device to emit laser pulses onto a subject. The laser pulses include a first pulse and a second pulse to place the subject in an excited state. The laser pulses also include a third pulse to stimulate emission of one or more third order signals from the subject. The system also includes a spectrometer to receive the one or more third order signals and to generate spectrum signals commensurate with intensities of the one or more third order signals. The system may further include circuitry configured to analyze the spectrum signals, generate one or more images of the subject based on the analysis, and construct one or more maps of positions of the subject based on the one or more images.

Various approaches to 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.

Laser speckle microrheology is used to determine a mechanical property of a biological tissue, namely, an elastic modulus. Speckle frames may be acquired by illuminating a coherent light and capturing back-scattered rays in parallel and cross-polarized states with respect to illumination. The speckle frames may be analyzed temporally to obtain diffuse reflectance profiles (DRPs) for the parallel-polarized and cross-polarized states. A scattering characteristic of particles in the biological tissue may be determined based on the DRPs, and a displacement characteristic may be determined based at least in part on a speckle intensity autocorrelation function and the scattering characteristic. A size characteristic of scattering particles may be determined based on the DRP for the parallel polarization state. The mechanical property may be calculated using the displacement and size characteristics.

This patent document discloses techniques, systems, and devices for detecting a target substance using optical nonlinear wave mixing for enhanced detection sensitivity and accuracy. In one aspect, a method for measuring α-synuclein in a body fluid of a patient with high detection sensitivity and accuracy and providing early stage Parkinson's disease detection is provided. The method may comprise: supplying to a capillary analyte cell a fluidic sample that includes a body fluid of a patient containing α-synuclein, wherein the capillary analyte cell is located in a nonlinear optical four-wave mixing device; directing laser light from the nonlinear optical four-wave mixing device into the capillary analyte cell to cause nonlinear optical four-wave mixing in the fluidic sample to generate a four-wave mixing signal that contains information on the α-synuclein in the fluidic sample; and processing the four-wave mixing signal to extract information on the α-synuclein in the fluidic sample.

For setting a laser-scanning fluorescence microscope to a correct alignment in which an intensity maximum of excitation light and an intensity minimum of fluorescence inhibition light coincide in a focal area of an objective lens, a structure in a sample marked with a fluorescent dye is scanned with the intensity maximum of the excitation light to generate first and second pictures of the sample, the first picture corresponding to a higher and the second picture corresponding to a lower intensity of the fluorescence inhibition light. A spatial offset of a first image of the structure in the first picture with regard to a second image of the structure in the second picture is calculated; and the intensity maximum of the excitation light is shifted with regard to the intensity minimum of the fluorescence inhibition light in the direction of the offset calculated to set the microscope to the correct alignment.

In a measurement requiring a high space resolution using S-BOTDR, a pulse train composed of a plurality of pulses having the interval between the pulses longer than the phonon lifetime is interpulse-code-modulated. A Golay code is used for the interpulse code modulation to eliminate the sidelobes of the correlation in using a technique of correlation. In a technique without using correlation, an Hadamard matrix is used for the interpulse code modulation and the resultant matrix is inverted in the signal processing.