Abstract: State-of-the-art portable Raman spectrometers use discrete free-space optical components that must be aligned well and that don't tolerate vibrations well. Conversely, the inventive spectrometers are made with monolithic photonic integration to fabricate some or all optical components on one or more planar substrates. Photonic integration enables dense integration of components, eliminates manual alignment and individual component assembly, and yields superior mechanical stability and resistance to shock or vibration. These features make inventive spectrometers especially suitable for use in high-performance portable or wearable sensors. They also yield significant performance advantages, including a large (e.g., 10,000-fold) increase in Raman scattering efficiency resulting from on-chip interaction of the tightly localized optical mode and the analyte and a large enhancement in spectral resolution and sensitivity resulting from the integration of an on-chip Fourier-transform spectrometer.

Abstract: A spectrometer includes an interferometer having a first interference arm and a second interference arm to produce interference patterns from incident light. At least one of the interference arms includes a series of cascaded optical switches connected by two (or more) waveguides of different lengths. Each optical switch directs the incident light into one waveguide or another, thereby changing the optical path length difference between the first interference arm and the second interference arm. This approach can be extended to multi-mode incident light by placing parallel interferometers together, each of which performs spectroscopy of one single mode in the multi-mode incident light. To maintain the compactness of the spectrometer, adjacent interferometers can share one interference arm.

Abstract: An apparatus for generating a spectral image includes a filter to receive incident light. The filter has a variable refractive index. The apparatus also includes a modulator, operably coupled to the filter, to modulate the variable refractive index of the filter so as to generate a plurality of optical patterns from the incident light. The plurality of optical patterns represents the spectral image and each optical pattern in the plurality of optical patterns corresponds to a different modulation of the variable refractive index. The apparatus further includes a detector, in optical communication with the filter, to detect the plurality of optical patterns.

Abstract: State-of-the-art portable Raman spectrometers use discrete free-space optical components that must be aligned well and that don't tolerate vibrations well. Conversely, the inventive spectrometers are made with monolithic photonic integration to fabricate some or all optical components on one or more planar substrates. Photonic integration enables dense integration of components, eliminates manual alignment and individual component assembly, and yields superior mechanical stability and resistance to shock or vibration. These features make inventive spectrometers especially suitable for use in high-performance portable or wearable sensors. They also yield significant performance advantages, including a large (e.g., 10,000-fold) increase in Raman scattering efficiency resulting from on-chip interaction of the tightly localized optical mode and the analyte and a large enhancement in spectral resolution and sensitivity resulting from the integration of an on-chip Fourier-transform spectrometer.

Abstract: A spectrometer includes an interferometer having a first interference arm and a second interference arm to produce interference patterns from incident light. At least one of the interference arms includes a series of cascaded optical switches connected by two (or more) waveguides of different lengths. Each optical switch directs the incident light into one waveguide or another, thereby changing the optical path length difference between the first interference arm and the second interference arm. This approach can be extended to multi-mode incident light by placing parallel interferometers together, each of which performs spectroscopy of one single mode in the multi-mode incident light. To maintain the compactness of the spectrometer, adjacent interferometers can share one interference arm.

Abstract: A spectrometer includes an interferometer having a first interference arm and a second interference arm to produce interference patterns from incident light. At least one of the interference arms includes a series of cascaded optical switches connected by two (or more) waveguides of different lengths. Each optical switch directs the incident light into one waveguide or another, thereby changing the optical path length difference between the first interference arm and the second interference arm. This approach can be extended to multi-mode incident light by placing parallel interferometers together, each of which performs spectroscopy of one single mode in the multi-mode incident light. To maintain the compactness of the spectrometer, adjacent interferometers can share one interference arm.

Abstract: An apparatus for generating a spectral image includes a filter to receive incident light. The filter has a variable refractive index. The apparatus also includes a modulator, operably coupled to the filter, to modulate the variable refractive index of the filter so as to generate a plurality of optical patterns from the incident light. The plurality of optical patterns represents the spectral image and each optical pattern in the plurality of optical patterns corresponds to a different modulation of the variable refractive index. The apparatus further includes a detector, in optical communication with the filter, to detect the plurality of optical patterns.

Abstract: A spectrometer includes an interferometer having a first interference arm and a second interference arm to produce interference patterns from incident light. At least one of the interference arms includes a series of cascaded optical switches connected by two (or more) waveguides of different lengths. Each optical switch directs the incident light into one waveguide or another, thereby changing the optical path length difference between the first interference arm and the second interference arm. This approach can be extended to multi-mode incident light by placing parallel interferometers together, each of which performs spectroscopy of one single mode in the multi-mode incident light. To maintain the compactness of the spectrometer, adjacent interferometers can share one interference arm.