A system for optical imaging of defects on unpatterned wafers that includes an illumination module, relay optics, a segmented polarizer, and a detector. The illumination module is configured to produce a polarized light beam incident on a selectable area of an unpatterned wafer. The relay optics is configured to collect and guide, radiation scattered off the area, onto the polarizer. The detector is configured to sense scattered radiation passed through the polarizer. The polarizer includes at least four polarizer segments, such that (i) boundary lines, separating the polarizer segments, are curved outwards relative to a plane, perpendicular to the segmented polarizer, unless the boundary line is on the perpendicular plane, and (ii) when the area comprises a typical defect, a signal-to-noise ratio of scattered radiation, passed through the polarizer segments, is increased as compared to when utilizing a linear polarizer.

A method for characterizing a photonic integrated circuit comprising includes coupling an evanescent field into a scattering element adjacent to a guiding layer of the photonic integrated circuit. The evanescent field is of an optical mode of light propagating in the guiding layer, and has an in-medium wavelength in the guiding layer. A maximum spatial dimension of the scattering element is less than the in-medium wavelength. The method includes scattering, with the scattering element, the coupled evanescent field as a reference scattered-signal. The method also includes detecting one of the reference scattered-signal and a signal derived therefrom.

An inspection device includes: a light source for outputting pulsed excitation light with a time width of 10 picoseconds to 10 nanoseconds; a nonlinear optical crystal for generating a terahertz wave by optical wavelength conversion of the pulsed excitation light; a polarization part for reflecting at least a part of a reflected wave of the terahertz wave reflected by an inspection target; and a detector for detecting the reflected wave reflected by the polarization part.

Interferometric speckle visibility spectroscopy methods, systems, and non-transitory computer readable media for recovering sample speckle field data or a speckle field pattern from an off-axis interferogram recorded by one or more sensors over an exposure time and determining sample dynamics of a sample being analyzed from speckle statistics of the speckle field data or the speckle field pattern.

Some implementations of the present disclosure provide a method that includes: irradiating a target surface with a process beam during a drilling process; in response to irradiating with the process beam, receiving a signal beam that contains light scattered from the target surface as well as light radiating from the target surface; splitting the signal beam into a first portion on a polarization arm and a second portion on a non-polarization arm; performing, on the polarization arm, a first plurality of polarization-dependent intensity and spectrum measurements of the first portion; performing, on the non-polarization arm, a second plurality of intensity and spectrum measurements of the second portion; and based on applying one or more machine learning techniques to at least portions of (i) the first plurality of polarization-dependent intensity and spectrum measurements, and (ii) the second plurality of intensity and spectrum measurements, determining a classification of the target surface.

The present disclosure relates to determining, in a fluid sample, particle(s) having a predetermined size or range of sizes within a detection zone using a particle detector, and includes: providing first and second lights to illuminate the sample within the detection zone; the first light being: a first polarisation at a first wavelength; a single wavelength having a first polarisation; or an unpolarised first wavelength; the second light being: a second polarisation at a second wavelength; the single wavelength having a second polarisation; or an unpolarised second wavelength; first sensor means obtaining a first response signal responsive to the first light impinging a particle; a second sensor means obtaining a second response signal responsive to the second light impinging a particle; determining a light scattering intensity at each light and a quotient thereof; and determining size of particle(s) by correlating light intensity values with values in a look-up table.

The hybrid measurement system includes an evanescent prism coupling spectroscopy (EPCS) sub-system and a light-scattering polarimetry (LSP) sub-system. The EPCS sub-system includes an EPCS light source system optically coupled to an EPCS detector system through an EPCS coupling prism. The LSP sub-system includes an LSP light source optically coupled to an optical compensator, which in turn is optically coupled to a LSP detector system via a LSP coupling prism. A support structure supports the EPCS and LSP coupling prisms to define a coupling prism assembly, which supports the two prisms at a measurement location. Stress measurements made using the EPCS and LSP sub-systems are combined to fully characterize the stress properties of a transparent chemically strengthened substrate. Methods of processing the EPCS and LSP measurements and enhanced configurations of the EPCS and LPS sub-systems to improve measurement accuracy are also disclosed.

A method of operating a detection system includes switching the system from a normal mode for sensing smoke to a high sensitivity mode for sensing airborne particles, such that in the high sensitivity mode the detection system is configured to discriminate between particles of diameters less than 2.5 micrometers and 10 micrometers. Transmitting light from one or more light sources of the detection system into a monitored space, and detecting scattered light at one or more light sensing devices of the detection system. The detection of scattered light is indicative of one or more indoor air quality conditions in the monitored space.

A method of operating a detection system includes switching the system from a normal mode for sensing smoke to a high sensitivity mode for sensing airborne particles, such that in the high sensitivity mode the detection system is configured to discriminate between particles of diameters less than 2.5 micrometers and 10 micrometers. Transmitting light from one or more light sources of the detection system into a monitored space, and detecting scattered light at one or more light sensing devices of the detection system. The detection of scattered light is indicative of one or more indoor air quality conditions in the monitored space.

The invention aims to provide an inspection device that can sensitively detect a defect even if intensity of scattered light reflected from an inspection object greatly varies depending on portions of the inspection object. An inspection device according to the invention uses a history of detection signals to predict whether a next detection signal level exceeds a threshold. When the detection signal level is predicted to exceed the threshold, operation of the device is beforehand changed such that the detection signal level does not exceed the threshold.