A tomographic imaging system receives measurements at a set of frequencies of a wavefield scattered by an internal structure of an object, recursively reconstructs an image of the internal structure of the object until a termination condition is met, and renders the reconstructed image. For a current iteration, the system adds a frequency to a previous set of frequencies used during a previous iteration to produce a current set of frequencies, such that the added frequency is higher than any frequency in the previous set of frequencies, and reconstructs a current image of the internal structure of the object that minimizes a difference between a portion of the scattered wavefield measured at the current set of frequencies and a wavefield synthetized from the current image. A previous image determined during the previous iteration initializes the reconstruction of the current image.

A method for machine learning enhanced optical-based screening for in-line wafer testing includes receiving optical spectra data for a wafer-under-test by performing scatterometry on the wafer-under-test, performing predictive model screening by applying a predictive model based on the optical spectra data, determining whether a device associated with the wafer-under-test is defective based on the predictive model screening, and if the device is determined to be defective, dynamically modifying a yield map associated with the wafer-under-test, including reassigning at least one die.

Systems and methods for sensing objects are provided. A sensing apparatus can include a sensor comprising a photo-detecting unit configured to absorb (i) a first incident light having a first wavelength to generate a first detecting signal and (ii) a second incident light having a second wavelength to generate a second detecting signal. The sensing apparatus can further include a calculation circuit coupled to the sensor. The calculation circuit can be configured to output a calculating result according to the first detecting signal and the second detecting signal. The sensing apparatus can further include an adjustment circuit coupled to the calculation circuit. The adjustment circuit can be configured to perform an adjustment to one or more functionalities associated with the sensing apparatus according to the calculating result.

Provided herein are an optical test platform and corresponding method of manufacturing the same. The test platform may include a shell defining a cavity for receiving a sample tube, a first aperture, and a second aperture. The first aperture and the second aperture of the shell may each be configured to optically couple the cavity with an exterior of the shell. The test platform may further include a first window and a second window embedded in the shell. The first window may seal a first aperture and the second window may seal a second aperture. The first window and second window may each permit the optical coupling of the cavity with the exterior of the shell. The first window and the second window may be optically coupled via the cavity, and the shell may prohibit optical coupling between the first window and the second window through the shell.

Methods and systems for calibrating metrology tool offset values to match measurement results across a fleet of metrology tools are presented herein. The calibration of offset values is based on measurements of inline, production wafers and does not require the use of specially fabricated and characterized quality control (QC) wafers. In this manner, the entire process flow to calibrate metrology tool offset values is automated and fully integrated within a high volume semiconductor fabrication process flow. In a further aspect, the implementation of a new offset value is regulated by one or more predetermined control limit values. In another further aspect, the measured values of a parameter of interest are adjusted to compensate for the effects of measurement time on the wafer under measurement.

We disclose methods and apparatus for measuring pH in a sub-surface volume of a diffusely scattering sample. Probe light is directed to an entry region on the sample surface, and collected from a collection region on the sample surface following diffuse scattering within the sample. The collection region is spatially offset from the entry region, so that when one or more Raman spectral features are detected in the collected probe light, a pH of the sub-surface volume can be determined from the spectral features.

Optical data is collected from an optical sensor of a dual wavelength, and in order to detect the fire from the collected optical data, an average value of a first wavelength, an average value of a second wavelength, and a ratio of the average values of the two wavelengths are calculated, and an amount of change of a slope of the ratio is used to detect the fire and determine the fire occurrence time. From the determined fire occurrence time, fire features are extracted from the optical data in real time according to defined rules to configure a data set. The data set may be used for learning and inference techniques to identify a fire or non-fire, a fire source, a combustion material, and the like.

Systems and methods which use an optical sensor and an electromagnetic sensor in cooperation for detecting concentrations of one or more materials in solutions are described. In operation according to embodiments of a cooperative optical and electromagnetic sensor material concentration detector, both an optical sensor and electromagnetic sensor are used in cooperation to detect a concentration of a material having a physical feature that is otherwise incompatible with one or the other sensors and/or a material for which measurement is affected by another material present in the sample. Embodiments are, for example, configured to provide a cooperative implementation of optical and electromagnetic sensors operable to detect concentrations of metal ions and acid in a solution, such as for use in real-time material concentration detection.

A method and a device for testing an electrode sheet, the method may comprise: acquiring M pieces of test data of a tab, wherein the tab protrudes from the end face of the electrode sheet along the first direction, the M pieces of test data are the test data of the tab at M consecutive positions along the second direction, the M pieces of test data are the test data of the height of the tab in the first direction, the second direction is perpendicular to the first direction, and M is a positive integer greater than 1; and determining whether the shape of the tab is normal based on the M pieces of test data.

A LIBS analysis system comprises a focusing lens arrangement having a focal plane; a laser for propagating a laser beam through the focusing lens arrangement to be focused at the focal plane; a detector for generating an output that is proportional to an intensity of incident electromagnetic radiation that is incident on the detector; a translation mechanism configured to cause a relative movement of the sample holder and the focusing lens arrangement to vary a position of the focal plane along the optical path with respect to the sample holder; and a controller configured to automatically control the translation mechanism to cause the relative movement of the sample holder and the focusing lens arrangement to achieve an optimum position at which the focal plane and an analysis region of the upper surface intersecting the optical path are at or are close to coincidence.