Abstract: Multi-spectral imaging systems include an excitation light source that produces an excitation beam having an excitation light spectrum. A programmable light source sequentially selects three or more excitation wavelength ranges from a plurality of excitation wavelength ranges based on code words defined by a selected code. Based on the code words, a sequence of encoded excitation beams is produced which are sequentially directed to a sample location. An imaging system such as a hyperspectral camera is situated to produce spectral images of a sample associated with a plurality of emission wavelength ranges in response to each of the encoded excitation beams. The spectral images are decoded to produce a spectral emission image corresponding to emitted intensity at the plurality of emission wavelengths as a function of excitation wavelength.

Abstract: A capillary comprises a capillary channel, an inner layer, and an outer layer, wherein the inner and outer layers comprise different silica materials. An axicon lens formed on a facet end of the capillary channel has a selected geometry, such that the inner layer has an axicon angle ? and a post angle ?. The inner layer may be fused silica and the outer layer may be borosilicate glass. The post angle ? is determined in part by an etch rate constant of the borosilicate glass and an etch rate constant of the fused silica in at least one etching reagent. Embodiments may comprise at least two capillary channels, and an axicon lens formed on a facet end of each of the at least two capillary channels. The capillary may be used as an electrospray emitter, optionally with light simultaneously while generating an electrospray.

Abstract: Described herein is an excitation emission matrix (EEM) spectrometer and method, comprising a multiplexer that encodes excitation light produced by at least one excitation light source; and a demultiplexer that decodes encoded light emitted from a sample, and produces an output indicative of a characteristic of the sample. Embodiments are described wherein the multiplexer and the demultiplexer may comprise FDM or OFDM, and wherein both the excitation light and the emitted light may be encoded using a DMA or a SLM. In some embodiments the same DMA or SLM may be used to encode the excitation light and the emitted light. In some embodiments excitation light may be encoded using a Walsh function, or the excitation light may be encoded using a Walsh function and the emitted light may be decoded using an inverse Hadamard transformation.

Abstract: A capillary comprises a capillary channel, an inner layer, and an outer layer, wherein the inner and outer layers comprise different silica materials. An axicon lens formed on a facet end of the capillary channel has a selected geometry, such that the inner layer has an axicon angle ? and a post angle ?. The inner layer may be fused silica and the outer layer may be borosilicate glass. The post angle a is determined in part by an etch rate constant of the borosilicate glass and an etch rate constant of the fused silica in at least one etching reagent. Embodiments may comprise at least two capillary channels, and an axicon lens formed on a facet end of each of the at least two capillary channels. The capillary may be used as an electrospray emitter, optionally with light simultaneously while generating an electrospray.

Abstract: Described herein is an excitation emission matrix (EEM) spectrometer and method, comprising a multiplexer that encodes excitation light produced by at least one excitation light source; and a demultiplexer that decodes encoded light emitted from a sample, and produces an output indicative of a characteristic of the sample. Embodiments are described wherein the multiplexer and the demultiplexer may comprise FDM or OFDM, and wherein both the excitation light and the emitted light may be encoded using a DMA or a SLM. In some embodiments the same DMA or SLM may be used to encode the excitation light and the emitted light. In some embodiments excitation light may be encoded using a Walsh function, or the excitation light may be encoded using a Walsh function and the emitted light may be decoded using an inverse Hadamard transformation.

Abstract: Described are methods for multi-wavelength cavity ring-down spectroscopy; comprising simultaneously and continuously irradiating an optical cavity with light at two or more different wavelengths, each light being intensity-modulated at a different modulation frequency, detecting the light of two or more wavelengths after the light has traveled through the optical cavity; measuring an optical loss of each detected light; and determining a characteristic of the optical cavity from the optical loss of each detected light. Also described are apparatus and systems for multi-wavelength cavity ring-down spectroscopy.

Abstract: Described are methods for multi-wavelength cavity ring-down spectroscopy; comprising simultaneously and continuously irradiating an optical cavity with light at two or more different wavelengths, each light being intensity-modulated at a different modulation frequency, detecting the light of two or more wavelengths after the light has travelled through the optical cavity; measuring an optical loss of each detected light; and determining a characteristic of the optical cavity from the optical loss of each detected light. Also described are apparatus and systems for multi-wavelength cavity ring-down spectroscopy.

Abstract: The invention provides a method and apparatus for measuring one or more optical properties, such as absorbance and refractive index, of a test medium such as a gas, a liquid, or solid material. The method comprises providing a passive optical waveguide loop comprising the test medium, launching in the optical loop an intensity-modulated light at a reference phase, detecting a phase of said light along the optical waveguide loop, and comparing the detected phase of said light along the loop with the reference phase, wherein the comparison provides information about one or more optical properties of the test medium.

Abstract: The invention relates to a method for sensing the presence of at least one analyte in a medium, comprising disposing in the medium a functionalized composite material such that the at least one analyte is absorbed by the functionalized composite material, the functionalized composite material having at least one optical property that is modulated by absorption of the at least one analyte; and measuring modulation of the at least one optical property of the functionalized composite material; wherein modulation of the at least one optical property of the functionalized composite material is indicative of the presence of the analyte in the medium. The invention also relates to an optical sensor for sensing the presence of at least one analyte in a medium, and a functionalized composite material having at least one optical property that is modulated upon absorption of one or more analyte.

Abstract: This invention relates to an optical pickup for a musical instrument based on one or more than one Bragg grating. In one embodiment the optical pickup includes at least one Bragg grating in physical contact with a vibrating structure of the musical instrument so as to receive acoustic vibration associated with the musical instrument being played, such that a spectrum of the Bragg grating is modulated upon receipt of the acoustic vibration. A light signal reflected from the at least one Bragg grating may be amplified and the output may be directed to a loud speaker or other real-time output device. The output may also be directed to a data acquisition system for storage and further processing. The optical pickup may include two Bragg gratings arranged as an optical cavity.

Abstract: The invention provides a method and apparatus for measuring one or more optical properties, such as absorbance and refractive index, of a test medium such as a gas, a liquid, or solid material. The method comprises providing a passive optical waveguide loop comprising the test medium, launching in the optical loop an intensity-modulated light at a reference phase, detecting a phase of said light along the optical waveguide loop, and comparing the detected phase of said light along the loop with the reference phase, wherein the comparison provides information about one or more optical properties of the test medium.

Abstract: The invention provides a method and apparatus for measuring one or more optical properties, such as absorbance and refractive index, of a test medium such as a gas, a liquid, or solid material. The method comprises providing a passive optical waveguide loop comprising the test medium, launching in the optical loop an intensity-modulated light at a reference phase, detecting a phase of said light along the optical waveguide loop, and comparing the detected phase of said light along the loop with the reference phase, wherein the comparison provides information about one or more optical properties of the test medium.

Abstract: The invention relates to optical sensors and systems and methods employing the sensors for detecting one or more compounds of interest in a test medium. In one embodiment an optical sensor comprising a long period grating and a solid phase microextraction (SPME) film is exposed to a test medium such that one or more compounds of interest are selectively partitioned into the solid phase microextraction film. At least one optical property of the sensor exposed to the test medium is compared with at least one corresponding optical property of the sensor in absence of the test medium; wherein a difference in the optical property is indicative of one or more compounds of interest in the test medium. The methods and systems may employ long period grating sensors with or without SPME films, and fiber loop ring-down spectroscopy to measure optical properties of the sensor.

Abstract: The invention relates to a method for sensing the presence of at least one analyte in a medium, comprising disposing in the medium a functionalized composite material such that the at least one analyte is absorbed by the functionalized composite material, the functionalized composite material having at least one optical property that is modulated by absorption of the at least one analyte; and measuring modulation of the at least one optical property of the functionalized composite material; wherein modulation of the at least one optical property of the functionalized composite material is indicative of the presence of the analyte in the medium. The invention also relates to an optical sensor for sensing the presence of at least one analyte in a medium, and a functionalized composite material having at least one optical property that is modulated upon absorption of one or more analyte.

Abstract: The invention relates to optical sensors and systems and methods employing the sensors for detecting one or more compounds of interest in a test medium. In one embodiment an optical sensor comprising a long period grating and a solid phase microextraction (SPME) film is exposed to a test medium such that one or more compounds of interest are selectively partitioned into the solid phase microextraction film. At least one optical property of the sensor exposed to the test medium is compared with at least one corresponding optical property of the sensor in absence of the test medium; wherein a difference in the optical property is indicative of one or more compounds of interest in the test medium. The methods and systems may employ long period grating sensors with or without SPME films, and fiber loop ring-down spectroscopy to measure optical properties of the sensor.

Abstract: The invention provides a method and apparatus for measuring one or more optical properties, such as absorbance and refractive index, of a test medium such as a gas, a liquid, or solid material. The method comprises providing a passive optical waveguide loop comprising the test medium, launching in the optical loop an intensity-modulated light at a reference phase, detecting a phase of said light along the optical waveguide loop, and comparing the detected phase of said light along the loop with the reference phase, wherein the comparison provides information about one or more optical properties of the test medium.

Abstract: The invention provides a method and apparatus for measuring one or more optical properties of a test medium, comprising providing an optical waveguide loop comprising a test medium, illuminating the optical waveguide loop with a plurality of light pulses, and detecting roundtrips of the light pulses at one or more locations along the loop, wherein the detected light pulses are indicative of one or more optical properties of the test medium. Preferably, ring-down time of said light pulses is determined. The invention provides measures of optical properties such as absorbance and refractive index of a test medium such as a gas, a liquid, and a solid material.

Abstract: The invention provides a method and apparatus for measuring one or more optical properties of a test medium, comprising providing an optical waveguide loop comprising a test medium, illuminating the optical waveguide loop with a plurality of light pulses, and detecting roundtrips of the light pulses at one or more locations along the loop, wherein the detected light pulses are indicative of one or more optical properties of the test medium. Preferably, ring-down time of said light pulses is determined. The invention provides measures of optical properties such as absorbance and refractive index of a test medium such as a gas, a liquid, and a solid material.