Abstract:
An illuminator/collector assembly (104) can deliver incident light (106) to a sample (102) and collect return light (112) returning from the sample (102). A sensor (114) can measure ray intensities as a function of ray position and ray angle for the collected return light (112). A ray selector can select a first subset of rays from the collected return light (112) at the sensor (114) that meet a first selection criterion. In some examples, the ray selector can aggregate ray intensities into bins, each bin corresponding to rays in the collected return light (112) that traverse within the sample (102) an estimated optical path length within a respective range of optical path lengths. A characterizer can determine a physical property of the sample (102), such as absorptivity, based on the ray intensities, ray positions, and ray angles for the first subset of rays. Accounting for variations in optical path length traversed within the sample can improve accuracy.
Abstract:
Methods and systems for measurement time distribution (1276, 1277, 1278) for referencing schemes are disclosed. The disclosed methods and systems are capable of dynamically changing the measurement time distribution based on the sample signal, reference signal, noise levels, and SNR. The methods and systems are configured with a plurality of measurement states, including a sample measurement state (1282), reference measurement state (1284), and dark measurement state (1286). In some examples, the measurement time distribution scheme can be based on the operating wavelength, the measurement location at the sampling interface, and/or targeted SNR. Examples of the disclosure further include systems and methods for measuring the different measurement states concurrently. Moreover, the systems and methods can include a high-frequency detector to eliminate or reduce decorrelated noise fluctuations that can lower the SNR.
Abstract:
This relates to systems (600) and methods for measuring a concentration and type of substance in a sample (620) at a sampling interface. The systems (600) includes a light source (602), one or more optics (606, 610, 612), one or more modulators (634, 636), a reference (608), a detector (630), and a controller (640). The systems and methods disclosed can be capable of accounting for drift originating from the light source, one or more optics, and the detector by sharing one or more components between different measurement light paths. Additionally, the systems can be capable of differentiating between different types of drift and eliminating erroneous measurements due to stray light with the placement of one or more modulators between the light source and the sample or reference. Furthermore, the systems can be capable of detecting the substance along various locations and depths within the sample by mapping a detector pixel and a microoptics to the location and depth in the sample.
Abstract:
A confocal inspection system can optically characterize a sample. An objective lens, or separate incident and return lenses, can deliver incident light from a light source to the sample, and can collect light from the sample. Confocal optics can direct the collected light onto a detector. The system can average the incident light over multiple locations at the sample, for example, by scanning the incident light with a pivotable mirror in the incident and return optical paths, or by illuminating and collecting with multiple spaced-apart confocal apertures. The system can average the collected light, for example, by directing the collected light onto a single-pixel detector, or by directing the collected light onto a multi-pixel detector and averaging the pixel output signals to form a single electronic signal. Averaging the incident and/or return light can be advantageous for structured or inhomogeneous samples.
Abstract:
Methods and systems for measuring one or more properties of a sample are disclosed. The methods and systems can include multiplexing measurements of signals associated with a plurality of wavelengths without adding any signal independent noise and without increasing the total measurement time. One or more levels of encoding, where, in some examples, a level of encoding can be nested within one or more other levels of encoding. Multiplexing can include wavelength, position, and detector state multiplexing. In some examples, SNR can be enhanced by grouping together one or more signals based on one or more properties including, but not limited to, signal intensity, drift properties, optical power detected, wavelength, location within one or more components, material properties of the light sources, and electrical power. In some examples, the system can be configured for optimizing the conditions of each group individually based on the properties of a given group.
Abstract:
Systems and methods for determining one or more properties of a sample are disclosed. The systems and methods disclosed can be capable of measuring along multiple locations and can reimage and resolve multiple optical paths within the sample. The system can be configured with one-layer or two-layers of optics suitable for a compact system. The optics can be simplified to reduce the number and complexity of the coated optical surfaces, etalon effects, manufacturing tolerance stack-up problems, and interference-based spectroscopic errors. The size, number, and placement of the optics can enable multiple simultaneous or non- simultaneous measurements at various locations across and within the sample. Moreover, the systems can be configured with an optical spacer window located between the sample and the optics, and methods to account for changes in optical paths due to inclusion of the optical spacer window are disclosed.
Abstract:
A confocal inspection system can optically characterize a sample. An objective lens, which can be a single lens or a combination of separate illumination and collection lenses, can have a pupil. The objective lens can deliver incident light to the sample through an annular illumination region of the pupil, and can collect scattered light returning from the sample to form collected light. Confocal optics can be positioned to receive the collected light. A detector can be configured with the confocal optics so that the detector generates signals from light received from a specified depth at or below a surface of the sample and rejects signals from light received from depths away from the specified depth. An optical element, such as a mask, a reconfigurable panel, or the detector, can define the annular collection region to be non-overlapping with the annular illumination region in the pupil.
Abstract:
A cascaded beam combiner can receive a plurality of incident beams, including first and last incident beams. The incident beams can have overlapping wavelength spectra that decrease in wavelength from the first incident beam to the last incident beam. Bandpass filters spectrally narrow the incident beams to form respective spectrally narrowed beams inside the cascaded beam combiner. The spectrally narrowed beams can have non-overlapping wavelength spectra that decrease in wavelength from a first spectrally narrowed beam to a last spectrally narrowed beam. Long wavelength pass filters sequentially combine components of the spectrally narrowed beams from the first spectrally narrowed beam to the last spectrally narrowed beam to form a cascaded beam. The cascaded beam combiner can form a multi-wavelength beam from the cascaded beam. The multi-wavelength beam can have a wavelength spectrum that includes the non-overlapping wavelength spectra of the spectrally narrowed beams.