Cavity buildup dispersion spectrometer and performing cavity buildup dispersion spectroscopy

Patent metadata

Field	Value
Publication number	US-11209314-B2
Application number	US-202017126118-A
Country	US
Kind code	B2
Filing date	Dec 18, 2020
Priority date	Dec 20, 2019
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A cavity buildup dispersion spectrometer includes a shutter that modulates coherent electromagnetic radiation at a shutter frequency; and produces modulated electromagnetic radiation; a frequency shifter that frequency shifts the modulated electromagnetic radiation to a shifter frequency and produces frequency shifted radiation; a resonator that produces cavity radiation from the frequency shifted radiation and the coherent electromagnetic radiation, receives an analyte; subjects the analyte to cavity radiation, and transmits the cavity radiation as transmitted electromagnetic radiation; and a receiver that: produces a detector signal from the transmitted electromagnetic radiation, such that the detector signal includes a beat frequency that corresponds to a change in a motion of resonator that includes a change in the distance between the mirrors or a change of refractive index of the analyte in the intracavity space.

First claim

What is claimed is:

1. A cavity buildup dispersion spectrometer comprising:
a shutter that receives coherent electromagnetic radiation, modulates the coherent electromagnetic radiation at a shutter frequency; and produces modulated electromagnetic radiation from the coherent electromagnetic radiation;
a frequency shifter in communication with the shutter and that receives the modulated electromagnetic radiation from the shutter, frequency shifts the modulated electromagnetic radiation by a shifter frequency; and produces frequency shifted radiation that is different from the modulated electromagnetic radiation by the shifter frequency;
a resonator in communication with the frequency shifter and comprising:
a plurality of mirrors separated by a distance;
an intracavity space interposed between the mirrors having the distance as a length; and
a plurality of cavity modes comprising: a primary cavity mode at a primary resonance frequency; and a secondary cavity mode at a secondary resonance frequency, such that the resonator:
receives the frequency shifted radiation from the frequency shifter;
receives coherent electromagnetic radiation;
produces cavity radiation, in the intracavity space, from the frequency shifted radiation and the coherent electromagnetic radiation;
receives an analyte in the intracavity space;
subjects the analyte to the cavity radiation
transmits the cavity radiation as transmitted electromagnetic radiation; and

a receiver in communication with the resonator and that:
receives the transmitted electromagnetic radiation from the resonator; and
produces detector signal from the transmitted electromagnetic radiation, such that the detector signal comprises a beat frequency that corresponds to a change in a motion of resonator that comprises a change in the distance between the mirrors or a change of refractive index of the analyte in the intracavity space.

2. The cavity buildup dispersion spectrometer of claim 1 , further comprising a frequency locking loop in communication with the resonator and the second coherent electromagnetic source and that:
receives second coherent radiation from the resonator;
produces a coherent electromagnetic radiation from the second coherent radiation; and
communicates the coherent electromagnetic radiation to the second coherent electromagnetic source.

3. The cavity buildup dispersion spectrometer of claim 2 , wherein the resonator produces the second coherent radiation from the cavity radiation, and the resonator communicates the second coherent radiation to the frequency locking loop.

4. The cavity buildup dispersion spectrometer of claim 3 , wherein the frequency locking loop comprises:
a receiver in communication with the resonator and receives the second coherent radiation from the resonator and produces an electronic error signal from the second coherent radiation;
a loop filter in communication with the receiver and that receives the electronic error signal from the receiver and produces a feedback control signal from the electronic error signal; and
an electromagnetic source in communication with the loop filter and that: receives the feedback control signal from the loop filter, produces a coherent electromagnetic radiation from the feedback control signal, and communicates the coherent electromagnetic radiation to a second coherent electromagnetic source and the resonator.

5. The cavity buildup dispersion spectrometer of claim 4 , further comprising the second coherent electromagnetic source in communication with the shutter and the electromagnetic source of the frequency locking loop and that:
receives the coherent electromagnetic radiation from the electromagnetic source;
produces the coherent electromagnetic radiation from the coherent electromagnetic radiation; and
communicates the coherent electromagnetic radiation to the frequency locking loop.

6. The cavity buildup dispersion spectrometer of claim 5 , wherein the resonator receives the coherent electromagnetic radiation from the electromagnetic source.

7. The cavity buildup dispersion spectrometer of claim 6 , further comprising a discriminator in communication with the resonator and the receiver and that:
receives the transmitted electromagnetic radiation from the resonator;
produces discriminator signal from the transmitted electromagnetic radiation; and
communicates the discriminator signal to the receiver, such that the receiver produces the detector signal from the discriminator signal.

8. The cavity buildup dispersion spectrometer of claim 1 , further comprising an analyzer in communication with the receiver and that:
receives the detector signal from the receiver; and
produces analyzer signal from the detector signal.

9. A process for performing cavity buildup dispersion spectroscopy with a cavity buildup dispersion spectrometer, the process comprising:
receiving, by a shutter, coherent electromagnetic radiation;
modulating, by the shutter, the coherent electromagnetic radiation at a shutter frequency;
producing, by the shutter, modulated electromagnetic radiation from the coherent electromagnetic radiation;
receiving, by a frequency shifter, the modulated electromagnetic radiation from the shutter;
frequency shifting, by the frequency shifter, the modulated electromagnetic radiation by a shifter frequency;
producing, by the frequency shifter, frequency shifted radiation shifted by the shifter frequency from the modulated electromagnetic radiation;
receiving, by a resonator, the frequency shifted radiation from the frequency shifter, the resonator comprising:
a plurality of mirrors separated by a distance;
an intracavity space interposed between the mirrors having the distance as a length; and
a plurality of cavity modes comprising: a primary cavity mode at a primary resonance frequency; and a secondary cavity mode at a secondary resonance frequency, such that the resonator;

receiving, by the resonator, coherent electromagnetic radiation;
producing, by the resonator, cavity radiation, in the intracavity space, from the frequency shifted radiation and the coherent electromagnetic radiation;
receiving, by the resonator, an analyte in the intracavity space;
subjecting the analyte to the cavity radiation;
transmitting the cavity radiation as transmitted electromagnetic radiation from the resonator;
receiving, by a receiver, the transmitted electromagnetic radiation from the resonator; and
producing, by the receiver, a detector signal from the transmitted electromagnetic radiation to perform cavity buildup dispersion spectroscopy,
wherein the detector signal comprises a beat frequency that corresponds to a change in a motion of resonator that comprises a change in the distance between the mirrors or a change of refractive index of the analyte in the intracavity space.

10. The process of claim 9 , further comprising:
receiving, by a frequency locking loop, the second coherent radiation from the resonator;
producing, by the frequency locking loop, a coherent electromagnetic radiation from the second coherent radiation; and
communicating the coherent electromagnetic radiation to the second coherent electromagnetic source from the frequency locking loop.

11. The process of claim 10 , further comprising:
producing, by the resonator, the second coherent radiation from the cavity radiation; and
communicating, by the resonator, the second coherent radiation to the frequency locking loop.

12. The process of claim 11 , further comprising:
receiving, by a receiver of the frequency locking loop, the second coherent radiation from the resonator;
producing, by the receiver, an electronic err

Assignees

• Government Of The Us Secretary Of Commerce

Inventors

• Fleisher Adam Joseph
• Gillis Keith Alan
• Hodges Joseph Terence

Classifications

• G01J3/10

  Arrangements of light sources specially adapted for spectrometry or colorimetry · CPC title

• G01J3/12

  Generating the spectrum; Monochromators · CPC title

• G01J3/0232

  using shutters · CPC title

• G01J3/021 Primary

  using plane or convex mirrors, parallel phase plates, or particular reflectors · CPC title

• G01N21/39

  using tunable lasers · CPC title