Abstract: In one embodiment, a method for auditing the results of a machine learning model includes: retrieving a set of state estimates for original time series data values from a database under audit; reversing the state estimation computation for each of the state estimates to produce reconstituted time series data values for each of the state estimates; retrieving the original time series data values from the database under audit; comparing the original time series data values pairwise with the reconstituted time series data values to determine whether the original time series and reconstituted time series match; and generating a signal that the database under audit (i) has not been modified where the original time series and reconstituted time series match, and (ii) has been modified where the original time series and reconstituted time series do not match.

Abstract: A broadband radiation source is disclosed. The system may include a plasma containment vessel configured to receive laser radiation from a pump source to sustain a plasma within gas flowed through the plasma containment vessel. The plasma containment vessel may be further configured to transmit at least a portion of broadband radiation emitted by the plasma. The system may also include a recirculation gas loop fluidically coupled to the plasma containment vessel. The recirculation gas loop may be configured to transport heated gas from an outlet of the plasma containment vessel, and further configured to transport cooled gas to an inlet of the plasma containment vessel.

Abstract: A system for illuminating a sample with a spectrally filtered illumination source includes an illumination source configured to generate a beam of illumination having a first set of wavelengths. In addition, the system includes a wavelength filtering sub-system, a sample stage, an illumination sub-system, a detector, and an objective to focus illumination from the surface of one or more samples and focus the collected illumination to the detector. Further, the wavelength filtering sub-system includes one or more first dispersive elements positioned to introduce spatial dispersion into the beam, a spatial filter element, and one or more dispersive elements positioned to remove spatial dispersion from the beam. The spatial filter element is further positioned to pass at least a portion of the beam including a second set of wavelengths, wherein the second set of wavelengths is a subset of the first set of wavelengths.

Abstract: A wideband spectrograph apparatus includes a first spectrograph assembly and one or more subsequent spectrograph assemblies. Each subsequent spectrograph assembly is optically coupled to a previous spectrograph assembly and is configured to receive a cascading beam from one or more dispersion elements of the previous spectrograph assembly. The first spectrograph assembly is configured for detecting illumination in a first wavelength range and the one or more subsequent spectrograph assemblies are configured for detecting illumination in wavelength ranges different from the first or any previous wavelength ranges to provide simultaneous sampling of different spectral portions of an input beam.

Abstract: A laser-sustained plasma lamp includes a gas containment structure configured to contain a volume of gas. The gas containment structure is configured to receive pump illumination from a pump laser for generating a plasma within the volume of gas. The gas containment structure includes one or more transmissive structures being at least partially transparent to the pump illumination from the pump laser and at least a portion of the broadband radiation emitted by the plasma. The one or more transmissive structures have a graded absorption profile so as to control heating of the one or more transmissive structures caused by the broadband radiation emitted by the plasma.

Abstract: A broadband radiation source is disclosed. The system may include a plasma containment vessel configured to receive laser radiation from a pump source to sustain a plasma within gas flowed through the plasma containment vessel. The plasma containment vessel may be further configured to transmit at least a portion of broadband radiation emitted by the plasma. The system may also include a recirculation gas loop fluidically coupled to the plasma containment vessel. The recirculation gas loop may be configured to transport heated gas from an outlet of the plasma containment vessel, and further configured to transport cooled gas to an inlet of the plasma containment vessel.

Abstract: Methods and systems for performing non-contact temperature measurements of optical elements with long wavelength infrared light are described herein. The optical elements under measurement exhibit low emissivity to long wavelength infrared light and are often highly reflective or highly transmissive to long wavelength infrared light. In one aspect, a material coating having high emissivity, low reflectivity, and low transmission at long wavelength IR wavelengths is disposed over selected portions of one or more optical elements of a metrology or inspection system. The locations of the material coating are outside the direct optical path of the primary measurement light employed by the metrology or inspection system to perform measurements of a specimen. Temperature measurements of the front and back surfaces of an IR-transparent optical element are performed with a single IR camera. Temperature measurements are performed through multiple optical elements in an optical path of a primary measurement beam.

Abstract: A wideband spectrograph apparatus includes a first spectrograph assembly and one or more subsequent spectrograph assemblies. Each subsequent spectrograph assembly is optically coupled to a previous spectrograph assembly and is configured to receive a cascading beam from one or more dispersion elements of the previous spectrograph assembly. The first spectrograph assembly is configured for detecting illumination in a first wavelength range and the one or more subsequent spectrograph assemblies are configured for detecting illumination in wavelength ranges different from the first or any previous wavelength ranges to provide simultaneous sampling of different spectral portions of an input beam.

Abstract: A system for forming a laser-sustained plasma includes a gas containment element, an illumination source configured to generate pump illumination, and a collector element configured to focus the pump illumination from the pumping source into the volume of the gas mixture in order to generate a plasma within the volume of the gas mixture that emits broadband radiation. The gas containment element may be configured to contain a volume of a gas mixture including a first gas component and a second gas component. The second gas component suppresses at least one of a portion of the broadband radiation associated with the first gas component or radiation by one or more excimers associated with the first gas component from a spectrum of radiation exiting the gas mixture.

Abstract: A system for controlling convective flow in a light-sustained plasma includes an illumination source configured to generate illumination, a bulb-less gas containment structure, and a collector element arranged to focus illumination from the illumination source into the volume of gas in order to generate a plasma within the volume of gas contained within the bulb-less gas containment structure. Further, the plasma is generated within a concave region of the collector element, where the collector element includes an opening through the collector element for propagating a portion of a plume of the plasma from a first region of the bulb-less gas containment structure to a second region of the bulb-less gas containment structure, wherein the first region of the bulb-less gas containment structure and the second region of the bulb-less gas containment structure are at least partially separated by a surface of the collector element.

Abstract: A system for forming a laser-sustained plasma includes a gas containment element, an illumination source configured to generate pump illumination, and a collector element configured to focus the pump illumination from the pumping source into the volume of the gas mixture in order to generate a plasma within the volume of the gas mixture that emits broadband radiation. The gas containment element may be configured to contain a volume of a gas mixture including a first gas component and a second gas component. The second gas component suppresses at least one of a portion of the broadband radiation associated with the first gas component or radiation by one or more excimers associated with the first gas component from a spectrum of radiation exiting the gas mixture.

Abstract: A laser-sustained plasma lamp includes a gas containment structure configured to contain a volume of gas. The gas containment structure is configured to receive pump illumination from a pump laser for generating a plasma within the volume of gas. The gas containment structure includes one or more transmissive structures being at least partially transparent to the pump illumination from the pump laser and at least a portion of the broadband radiation emitted by the plasma. The one or more transmissive structures have a graded absorption profile so as to control heating of the one or more transmissive structures caused by the broadband radiation emitted by the plasma.

Abstract: Methods and systems for performing non-contact temperature measurements of optical elements with long wavelength infrared light are described herein. The optical elements under measurement exhibit low emissivity to long wavelength infrared light and are often highly reflective or highly transmissive to long wavelength infrared light. In one aspect, a material coating having high emissivity, low reflectivity, and low transmission at long wavelength IR wavelengths is disposed over selected portions of one or more optical elements of a metrology or inspection system. The locations of the material coating are outside the direct optical path of the primary measurement light employed by the metrology or inspection system to perform measurements of a specimen. Temperature measurements of the front and back surfaces of an IR-transparent optical element are performed with a single IR camera. Temperature measurements are performed through multiple optical elements in an optical path of a primary measurement beam.

Abstract: A system for forming a laser-sustained plasma includes a gas containment element, an illumination source configured to generate pump illumination, and a collector element. The gas containment element is configured to contain a volume of a gas mixture. The collector element is configured to focus the pump illumination from the pumping source into the volume of the gas mixture contained within the gas containment element in order to generate a plasma within the volume of the gas mixture that emits broadband radiation. The gas mixture filters one or more selected wavelengths of radiation emitted by the plasma.

Abstract: A system for illuminating a sample with a spectrally filtered illumination source includes an illumination source configured to generate a beam of illumination having a first set of wavelengths. In addition, the system includes a wavelength filtering sub-system, a sample stage, an illumination sub-system, a detector, and an objective to focus illumination from the surface of one or more samples and focus the collected illumination to the detector. Further, the wavelength filtering sub-system includes one or more first dispersive elements positioned to introduce spatial dispersion into the beam, a spatial filter element, and one or more dispersive elements positioned to remove spatial dispersion from the beam. The spatial filter element is further positioned to pass at least a portion of the beam including a second set of wavelengths, wherein the second set of wavelengths is a subset of the first set of wavelengths.

Abstract: The inspection of a sample with VUV light from a laser sustained plasma includes generating pumping illumination including a first selected wavelength, or range of wavelength, containing a volume of gas suitable for plasma generation, generating broadband radiation including a second selected wavelength, or range of wavelengths, by forming a plasma within the volume of gas by focusing the pumping illumination into the volume of gas, illuminating a surface of a sample with the broadband radiation emitted from the plasma via an illumination pathway, collecting illumination from a surface of the sample, focusing the collected illumination onto a detector via a collection pathway to form an image of at least a portion of the surface of the sample and purging the illumination pathway and/or the collection pathway with a selected purge gas.

Abstract: A system for controlling convective flow in a light-sustained plasma includes an illumination source configured to generate illumination, a plasma cell including a bulb for containing a volume of gas, a collector element arranged to focus illumination from the illumination source into the volume of gas in order to generate a plasma within the volume of gas contained within the bulb. Further, the plasma cell is disposed within a concave region of the collector element, where the collector element includes an opening for propagating a portion of a plume of the plasma to a region external to the concave region of the collect element.

Abstract: A system for forming a laser-sustained plasma includes a gas containment element, an illumination source configured to generate pump illumination, and a collector element. The gas containment element is configured to contain a volume of a gas mixture. The collector element is configured to focus the pump illumination from the pumping source into the volume of the gas mixture contained within the gas containment element in order to generate a plasma within the volume of the gas mixture that emits broadband radiation. The gas mixture filters one or more selected wavelengths of radiation emitted by the plasma.

Abstract: A system for controlling convective flow in a light-sustained plasma includes an illumination source configured to generate illumination, a plasma cell including a bulb for containing a volume of gas, a collector element arranged to focus illumination from the illumination source into the volume of gas in order to generate a plasma within the volume of gas contained within the bulb. Further, the plasma cell is disposed within a concave region of the collector element, where the collector element includes an opening for propagating a portion of a plume of the plasma to a region external to the concave region of the collect element.

Abstract: The inspection of a sample with VUV light from a laser sustained plasma includes generating pumping illumination including a first selected wavelength, or range of wavelength, containing a volume of gas suitable for plasma generation, generating broadband radiation including a second selected wavelength, or range of wavelengths, by forming a plasma within the volume of gas by focusing the pumping illumination into the volume of gas, illuminating a surface of a sample with the broadband radiation emitted from the plasma via an illumination pathway, collecting illumination from a surface of the sample, focusing the collected illumination onto a detector via a collection pathway to form an image of at least a portion of the surface of the sample and purging the illumination pathway and/or the collection pathway with a selected purge gas.