Abstract: An optical imaging system includes an object-side lens, a prism, an EMR reflection filter, an image-side lens, and an image sensor. The EMR reflection filter is disposed substantially at a pupil plane of the optical imaging system. The optical imaging system is configured to receive and filter electromagnetic radiation and to reflect the filtered electromagnetic radiation back into the prism, which then passes the filtered electromagnetic radiation to a detector for imaging the filtered radiation. The imaging system is readily reconfigurable by virtue of having a changeable EMR reflection filter.

Abstract: An integral field spectral imager has a plurality of optical homogenizers. Each optical homogenizer is in-register with a corresponding different superpixel in a superpixel array and is configured to spatially homogenize incident EMR and to pass the spatially homogenized EMR to a spectral filter in an array of spectral filters, thence to the in-register, corresponding different superpixel. Baffles are included to maximize confinement of the spatially homogenized EMR passed by a single optical homogenizer to the in-register, corresponding different superpixel so as to minimize crosstalk between superpixels. Optical homogenizers and baffles are designed to produce a pattern of homogenized EMR on a superpixel, regardless of where incident EMR is received on an optical homogenizer. Methods for using embodiments of the spectral imager in a variety of spectral bands in the EMR spectrum enable determining spectral information about incident EMR.

Abstract: An integral field spectral imager has a plurality of optical homogenizers. Each optical homogenizer is in-register with a corresponding different superpixel in a superpixel array and is configured to spatially homogenize incident EMR and to pass the spatially homogenized EMR to a spectral filter in an array of spectral filters, thence to the in-register, corresponding different superpixel. Baffles are included to maximize confinement of the spatially homogenized EMR passed by a single optical homogenizer to the in-register, corresponding different superpixel so as to minimize crosstalk between superpixels. Optical homogenizers and baffles are designed to produce a pattern of homogenized EMR on a superpixel, regardless of where incident EMR is received on an optical homogenizer. Methods for using embodiments of the spectral imager in a variety of spectral bands in the EMR spectrum enable determining spectral information about incident EMR.

Abstract: An integral field spectral imager has a plurality of optical homogenizers. Each optical homogenizer is in-register with a corresponding different superpixel in a superpixel array and is configured to spatially homogenize incident EMR and to pass the spatially homogenized EMR to a spectral filter in an array of spectral filters, thence to the in-register, corresponding different superpixel. Baffles are included to maximize confinement of the spatially homogenized EMR passed by a single optical homogenizer to the in-register, corresponding different superpixel so as to minimize crosstalk between superpixels. Optical homogenizers and baffles are designed to produce a pattern of homogenized EMR on a superpixel, regardless of where incident EMR is received on an optical homogenizer. Methods for using embodiments of the spectral imager in a variety of spectral bands in the EMR spectrum enable determining spectral information about incident EMR.

Abstract: Methods and sensors for the detection, identification, and quantification of one or more gas species, including volatile organic compounds, in a test sample are described. Methods employ gas sensors comprising a diffusion matrix present on the sensor surface. A gas analyte in a test sample diffuses through the matrix and is detected upon interaction of the analyte with the sensor. A response profile of a gas sensor to a gas analyte in the test sample is compared to a control gas sensor response profile determined in a similar manner for a known gas species. Comparisons of test sample and control sample sensor response profiles enable detection, identification, and quantification of a gas species analyte in a test sample.

Abstract: A light field relay has an array of microlenses, an array of transducers, and an array of output optics. Microlenses focus one or more than one selected portions of an incident light field to separate corresponding transducers. Each corresponding transducer receives and transduces a single portion of focused light and emits the transduced light. Corresponding different output optics substantially collimate the transduced light and emit the substantially collimated light as an emitted light field. The light field relay may collect infrared light in one or more selected portions of an incident light field, transduce the infrared light to visible light, substantially collimate the transduced visible light, and emit a visible light field.

Abstract: A tunable notch filter for operation in reflection mode comprises an antenna layer positioned on a transmissive substrate and a mirror layer positioned on a support substrate. The antenna layer and the mirror layer are positioned on opposite sides of a gap and facing each other, the gap having a gap distance. The notch filter is tuned by adjusting the gap distance between the antenna layer and the mirror layer. Tuning the notch filter to a selected state can cause the filter to selectively attenuate the reflection of at least some electromagnetic radiation that is incident on the transmissive substrate and enters the notch filter.

Abstract: A light field relay has an array of microlenses, an array of transducers, and an array of output optics. Microlenses focus one or more than one selected portions of an incident light field to separate corresponding transducers. Each corresponding transducer receives and transduces a single portion of focused light and emits the transduced light. Corresponding different output optics substantially collimate the transduced light and emit the substantially collimated light as an emitted light field. The light field relay may collect infrared light in one or more selected portions of an incident light field, transduce the infrared light to visible light, substantially collimate the transduced visible light, and emit a visible light field.

Abstract: Methods use a tunable notch filter for constructing a spectral map of electromagnetic radiation in a selected spectral band that is incident on a notch filter for a plurality of time periods. Electromagnetic radiation is passed by an electronically tuned notch filter to a detector array for the plurality of selected time periods, and the detector response is determined. For at least a first selected time period the notch filter is tuned to selectively attenuate the passing of one or more selected sub-bands of electromagnetic radiation in the selected spectral band. Information about the selectively attenuated radiation is determined and used along with information about the radiation passed to the detector array for each time period to construct a spectral map. Electronically tunable notch filters may be made with metamaterials such as patterned graphene.

Abstract: Methods use a tunable notch filter for constructing a spectral map of electromagnetic radiation in a selected spectral band that is incident on a notch filter for a plurality of time periods. Electromagnetic radiation is passed by an electronically tuned notch filter to a detector array for the plurality of selected time periods, and the detector response is determined. For at least a first selected time period the notch filter is tuned to selectively attenuate the passing of one or more selected sub-bands of electromagnetic radiation in the selected spectral band. Information about the selectively attenuated radiation is determined and used along with information about the radiation passed to the detector array for each time period to construct a spectral map. Electronically tunable notch filters may be made with metamaterials such as patterned graphene.

Abstract: An apparatus comprises a housing defining a chamber that has a liquid disposed therein, and a sensor submerged in the liquid. The sensor comprises a porous conductive film on a substrate, and the film comprises chemiresistive semiconducting metal oxide structures. The sensor also comprises an electrode pair operably connected to the porous conductive film for generating electric current in the film and for detecting a change in an electrical property of the film. The apparatus can be used to detect, identify, and quantify ions and molecules in a liquid sample. Molecules and ions, in a liquid sample, that interact with the porous conductive film can cause a change in an electrical property of the film. The change in electrical property of the film can be correlated with the presence and amount of the molecules or ions.

Abstract: A tunable notch filter for operation in reflection mode comprises an antenna layer positioned on a transmissive substrate and a mirror layer positioned on a support substrate. The antenna layer and the mirror layer are positioned on opposite sides of a gap and facing each other, the gap having a gap distance. The notch filter is tuned by adjusting the gap distance between the antenna layer and the mirror layer. Tuning the notch filter to a selected state can cause the filter to selectively attenuate the reflection of at least some electromagnetic radiation that is incident on the transmissive substrate and enters the notch filter.

Abstract: An apparatus comprises a housing defining a chamber that has a liquid disposed therein, and a sensor submerged in the liquid. The sensor comprises a porous conductive film on a substrate, and the film comprises chemiresistive semiconducting metal oxide structures. The sensor also comprises an electrode pair operably connected to the porous conductive film for generating electric current in the film and for detecting a change in an electrical property of the film. The apparatus can be used to detect, identify, and quantify ions and molecules in a liquid sample. Molecules and ions, in a liquid sample, that interact with the porous conductive film can cause a change in an electrical property of the film. The change in electrical property of the film can be correlated with the presence and amount of the molecules or ions.

Abstract: Methods and sensors for detection and quantification of one or more analyte in a test sample are described. A response profile of an ion sensor to a control sample of a known interrogator ion is determined. The ion sensor is exposed to a test sample then to a second sample comprising the known interrogator ion, and a test sample response profile of the ion sensor is determined. One or more test sample sensor response profiles are compared with one or more control sensor response profiles for detecting, identifying, and quantifying one or more analytes in the test sample.

Abstract: Methods and sensors for detection and quantification of one or more analyte in a test sample are described. A response profile of a gas sensor to a control sample of a known interrogator gas is determined. The gas sensor is exposed to a test sample then to a second sample comprising the known interrogator gas, and a test sample response profile of the gas sensor is determined. One or more test sample sensor response profiles are compared with one or more control sensor response profiles for detecting, identifying, and quantifying one or more analytes in the test sample.

Abstract: A rectifier is provided for converting an oscillating electromagnetic field into a direct current and comprises an electrically conductive antenna layer configured to absorb electromagnetic radiation, an electrically conductive mirror layer configured to provide an electromagnetic mirror charge of the antenna layer, an electrically insulating tunnel barrier layer positioned between the antenna layer and the mirror layer, and an electronic circuit electrically connected between the conductive mirror layer and the conductive antenna layer. The rectifier employs a metamaterial configuration for room temperature rectification of radiation in regions of the electromagnetic spectrum comprising the MWIR and LWIR regions. Methods for use of the rectifier in rectifying and detecting radiation are described.

Abstract: A compact, mapping spectrometer and various embodiments of the spectrometer are described. Methods for performing high-resolution spectroscopic, spatial, and polarimetric analyses of electromagnetic radiation across the complete electromagnetic spectrum, using spectrometer embodiments of the invention, are also described. The spectrometer and associated methods are useful for producing spectral and hyperspectral images associated with the incoming radiation and for identifying other information about electromagnetic radiation of interest.

Abstract: A rectifier is provided for converting an oscillating electromagnetic field into a direct current and comprises an electrically conductive antenna layer configured to absorb electromagnetic radiation, an electrically conductive mirror layer configured to provide an electromagnetic mirror charge of the antenna layer, an electrically insulating tunnel barrier layer positioned between the antenna layer and the mirror layer, and an electronic circuit electrically connected between the conductive mirror layer and the conductive antenna layer. The rectifier employs a metamaterial configuration for room temperature rectification of radiation in regions of the electromagnetic spectrum comprising the MWIR and LWIR regions. Methods for use of the rectifier in rectifying and detecting radiation are described.

Abstract: Methods and sensors for detection and quantification of one or more analyte in a test sample are described. A response profile of a gas sensor to a control sample of a known interrogator gas is determined. The gas sensor is exposed to a test sample then to a second sample comprising the known interrogator gas, and a test sample response profile of the gas sensor is determined. One or more test sample sensor response profiles are compared with one or more control sensor response profiles for detecting, identifying, and quantifying one or more analytes in the test sample.

Abstract: Methods and sensors for the detection, identification, and quantification of one or more gas species, including volatile organic compounds, in a test sample are described. Methods employ gas sensors comprising a diffusion matrix present on the sensor surface. A gas analyte in a test sample diffuses through the matrix and is detected upon interaction of the analyte with the sensor. A response profile of a gas sensor to a gas analyte in the test sample is compared to a control gas sensor response profile determined in a similar manner for a known gas species. Comparisons of test sample and control sample sensor response profiles enable detection, identification, and quantification of a gas species analyte in a test sample.