Miniaturized Fourier-transform Raman spectrometer systems and methods
First Claim
1. A system, comprising:
- a light source to emit a probe beam;
a probe waveguide, in optical communication with the light source, to receive the probe beam and cause at least a portion of the probe beam to interact with a sample, the interaction between the probe beam and the sample generating a Raman signal;
a filter, in optical communication with the sample, to transmit the Raman signal and block the probe beam;
a Fourier transform spectrometer in optical communication with the filter, the Fourier transform spectrometer comprising;
a beam splitter to split the Raman signal into a first portion and a second portion;
a first interference arm, in optical communication with the beam splitter, to receive the first portion of the Raman Signal, the first interference arm comprising;
a first optical switch switchable between a first state and a second state;
a first reference waveguide having a first optical path length L1 to receive the first portion of the Raman signal when the first optical switch is in the first state; and
a first variable waveguide having a second optical path length L2, different than the first optical path length L1, to receive the first portion of the Raman signal when the first optical switch is in the second state; and
a second interference arm, in optical communication with the beam splitter, to receive the second portion of the Raman Signal; and
at least one detector, in optical communication with the first interference arm and the second interference arm, to detect interference of the first portion of the Raman signal from the first interference arm and the second portion of the Raman signal from the second interference arm.
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Accused Products
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.
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Citations
19 Claims
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1. A system, comprising:
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a light source to emit a probe beam; a probe waveguide, in optical communication with the light source, to receive the probe beam and cause at least a portion of the probe beam to interact with a sample, the interaction between the probe beam and the sample generating a Raman signal; a filter, in optical communication with the sample, to transmit the Raman signal and block the probe beam; a Fourier transform spectrometer in optical communication with the filter, the Fourier transform spectrometer comprising; a beam splitter to split the Raman signal into a first portion and a second portion; a first interference arm, in optical communication with the beam splitter, to receive the first portion of the Raman Signal, the first interference arm comprising; a first optical switch switchable between a first state and a second state; a first reference waveguide having a first optical path length L1 to receive the first portion of the Raman signal when the first optical switch is in the first state; and a first variable waveguide having a second optical path length L2, different than the first optical path length L1, to receive the first portion of the Raman signal when the first optical switch is in the second state; and a second interference arm, in optical communication with the beam splitter, to receive the second portion of the Raman Signal; and at least one detector, in optical communication with the first interference arm and the second interference arm, to detect interference of the first portion of the Raman signal from the first interference arm and the second portion of the Raman signal from the second interference arm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of Raman spectroscopy, the method comprising:
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emitting a probe beam from a laser; guiding the probe beam from the laser to a sample via a first waveguide integrated in or on a substrate; coupling the probe beam out of the first waveguide to a sample, the probe beam causing the sample to generate a Raman signal; coupling the Raman signal into a second waveguide integrated in or on the substrate; splitting the Raman signal into a first portion and a second portion; guiding the first portion through a first interference arm integrated in or on the substrate, the first interference arm comprising; an optical switch switchable between a first state and a second state; a reference waveguide having a first optical path length L1 to receive the first portion when the first optical switch is in the first state; and a variable waveguide having a second optical path length L2, different than the first optical path length L1, to receive the first portion when the first optical switch is in the second state; and guiding the second portion through a second interference arm integrated in or on the substrate; and interfering the first portion and the second portion at a detector coupled to the first interference arm and the second interference arm. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A Raman spectroscopy system comprising:
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a substrate; a laser, integrated on the substrate, to emit a probe beam; a first waveguide, integrated on or in the substrate in optical communication with the laser, to guide the probe beam; a lens, integrated on or in the substrate in optical communication with the first waveguide, to direct the probe beam to a sample and to collect a Raman signal from the sample in response to the probe beam; at least one second waveguide, integrated on or in the substrate in optical communication with the lens, to guide the Raman signal; a spectrometer, integrated on or in the substrate in optical communication with the at least one second waveguide, to separate the Raman signal into spectral bins; and at least one photodetector, integrated on or in the substrate in optical communication with the spectrometer, to detect an output of the spectrometer, wherein the spectrometer comprises; an optical switch switchable between a first state and a second state; a reference waveguide having a first optical path length L1 to receive a first portion of the Raman signal when the first optical switch is in the first state; and a variable waveguide having a second optical path length L2, different than the first optical path length L1, to receive the first portion when the first optical switch is in the second state. - View Dependent Claims (19)
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Specification