Active remote sensing using a spectral lock-in technique
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H01J-040/14
H01J-005/16
출원번호
US-0419797
(2003-04-22)
발명자
/ 주소
Neff, Benjamin R.
Pruitt, Jeff D.
Gypson, Matthew L.
Dobbs, Michael E.
출원인 / 주소
ITT Manufacturing Enterprises, Inc.
대리인 / 주소
RatnerPrestia
인용정보
피인용 횟수 :
14인용 특허 :
4
초록▼
A system for sensing a characteristic of a sample may include a tunable source configured to emit optical radiation that varies over a wavelength range at a first frequency and a reference source configured to emit optical radiation that varies in amplitude at a second frequency. A science detector
A system for sensing a characteristic of a sample may include a tunable source configured to emit optical radiation that varies over a wavelength range at a first frequency and a reference source configured to emit optical radiation that varies in amplitude at a second frequency. A science detector may be configured to detect the optical radiation from the tunable source and the reference source after interaction with the sample and generate a science signal. A number of lock-in amplifiers may be respectively configured to generate components of the science signal that are present at the first and second frequencies. A processor may be configured to determine a characteristic of the sample based on the components of the science signal that are present at the first and second frequencies.
대표청구항▼
1. A system for sensing a sample, comprising:a first tunable source configured to emit first optical radiation over a range of wavelengths that is swept at a first frequency; a second fixed source configured to emit second optical radiation at a predetermined fixed wavelength that is amplitude modul
1. A system for sensing a sample, comprising:a first tunable source configured to emit first optical radiation over a range of wavelengths that is swept at a first frequency; a second fixed source configured to emit second optical radiation at a predetermined fixed wavelength that is amplitude modulated at a second frequency, the first tunable source and the second fixed source emitted simultaneously; a first detector configured to detect the first and second optical radiation scattered/reflected from the sample and generate a first detection signal; a first lock-in amplifier configured to process the first detection signal based on the first frequency to produce a first output signal; and a second lock-in amplifier configured to process the first detection signal based on the second frequency to produce a second output signal, wherein the first and second frequencies are not harmonically related to each other and are preselected to reduce inter-modulation between each other. 2. The system of claim 1, further comprising:a coupler connected to the first source and the second source and configured to combine the first optical radiation and the second optical radiation into a combined signal; and an optical amplifier connected to the coupler and configured to amplify the combined signal. 3. The system of claim 1, further comprising:a second detector configured to detect the first and second optical radiation before interaction with the sample and generate a second detection signal; a third lock-in amplifier configured to process the second detection signal based on the first frequency to produce a third output signal; and a fourth lock-in amplifier configured to process the second detection signal based on the second frequency to produce a fourth output signal. 4. The system of claim 3, wherein the sample includes a spectral feature within the range of wavelengths, the system further comprising:a processor configured to process the first output signal, the second output signal, the third output signal, and the fourth output signal to obtain information relating to the spectral feature. 5. The system of claim 4, wherein the information includes a concentration of the sample.6. The system of claim 1, whereinthe system is disposed in an aircraft or a satellite for remotely sensing the sample. 7. A method of remotely sensing a sample, comprising:transmitting a beam of optical radiation toward the sample, the beam including a first tunable source that is swept over a range or wavelengths periodically varying at a first frequency and a second fixed source at a predetermined fixed wavelength that is amplitude modulated at an amplitude varying at a second frequency, the first tunable source and the second fixed source transmitted simultaneously; detecting the beam of optical radiation after scattering/reflection from the sample to produce a detection signal; determining a portion of the detection signal that is present at the first frequency; determining another portion of the detection signal that is present at the second frequency; and obtaining information about the sample based on the portion of the detection signal and the another portion of the detection signal, wherein the first and second frequencies are not harmonically related to each other and are preselected to reduce inter-modulation between each other. 8. The method of claim 7, further comprising:generating a tuning signal that periodically varies over the wavelengths at the first frequency; generating a reference signal that is amplitude modulated at the second frequency; and combining the tuning signal and the reference signal into the beam of optical radiation. 9. The method of claim 8, further comprising:amplifying the beam of optical radiation before the transmitting. 10. The method of claim 7, wherein the determining a portion of the detection signal uses a lock-in technique and an external reference signal at the first frequency, andwherein the determining another portion of the detection signal uses the lock-in technique and another external reference signal at the second frequency. 11. The method of claim 7, wherein the information about the sample includes an area of a spectral feature of the sample.12. A system for sensing a characteristic of a sample, comprising:a tunable source configured to emit optical radiation that varies over a wavelength range at a first frequency; a reference source configured to emit optical radiation at a predetermined fixed wavelength that varies in amplitude at a second frequency, the tunable source and the reference source emitted simultaneously; a science detector configured to detect the optical radiation from the tunable source and the reference source after scattering/reflection from the sample and generate a science signal; a plurality of lock-in amplifiers respectively configured to generate components of the science signal that are present at the first and second frequencies; and a processor configured to determine a characteristic of the sample based on the components of the science signal that are present at the first and second frequencies, wherein the first and second frequencies are not harmonically related to each other and are preselected to reduce inter-modulation between each other. 13. The system of claim 12, further comprising:a coupler configured to combine the optical radiation from the tunable source and the reference source into a combined signal. 14. The system of claim 12, further comprising:an optical amplifier connected to the coupler and configured to amplify the combined signal and transmit the combined signal toward the sample. 15. The system of claim 12, further comprising:a reference detector configured to detect the optical radiation from the tunable source and the reference source before scattering/reflection from the sample and generate a reference signal; a second plurality of lock-in amplifiers respectively configured to generate components of the reference signal that are present at the first and second frequencies. 16. The system of claim 15, wherein the processor is further configured to determine the characteristic of the sample based on the components of the reference signal that are present at the first and second frequencies.17. The system of claim 12, wherein the characteristic includes a concentration of the sample.18. A method of remotely sensing a target, comprising:generating a first beam of optical radiation that is wavelength modulated at a first frequency; generating a second beam of optical radiation that is amplitude modulated at a second frequency, wherein the first and second frequencies are not harmonically related to each other and are preselected to reduce inter-modulation between each other; combining the first and second beams of optical radiation for transmission to the target; generating first and second reference signals at the first and second frequencies; and detecting first radiation and second radiation scattered/reflected from the target using a phase sensitive technique and the first and second reference signals. 19. The method of claim 18, wherein the first beam of radiation varies over a predetermined range of wavelengths, andwherein the second beam of radiation has a reference wavelength that falls outside the predetermined range of wavelengths. 20. The method of claim 18, further comprising:amplifying the first and second beams of optical radiation after the combining. 21. The method of claim 18, further comprising:detecting third radiation and fourth radiation before scattering/reflection from the target using the phase sensitive technique and the first and second reference signals. 22. The method of claim 21, further comprising:determining one or more characteristics of the target based on the first radiation, the second radiation, the third radiation, and the fourth radiation. 23. The method of claim 18, whereingenerating and combining the first and second beams are performed in an aircraft or a satellite.
연구과제 타임라인
LOADING...
LOADING...
LOADING...
LOADING...
LOADING...
이 특허에 인용된 특허 (4)
Theodore C. Oakberg, Measurement of waveplate retardation using a photoelastic modulator.
Brand Joel A. ; Monlux Garth A. ; Zmarzly Patrick ; Fetzer Gregory J. ; Halsted Benjamin C. ; Groff Kenneth W. ; Lee Jamine ; Goldstein Neil ; Richtsmeier Steven ; Bien Fritz, Method and apparatus for in situ gas concentration measurement.
Partridge Roger H. (Leatherhead GBX) Bradsell Robert H. (Hampton GBX) Woods Peter T. (Walton-on-Thames GBX), Optical wavelength modulated long-path gas monitoring apparatus.
Schneider,Thomas Wayne; Jones,James Pendell; Armstrong,Wayne; Rezac,Jeromy; Shanna,Ratnesar Shumate Ashni; Randolph,Claudia; Almassy,Robert, Air sampler module for enhancing the detection capabilities of a chemical detection device or system.
Shakespeare, Tarja T.; Shakespeare, John F., Apparatus and method for measuring and/or controlling ultraviolet-activated materials in a paper-making process.
Ponsardin, Patrick Louis; Kletecka, Christopher Scott; Rezac, Jeromy Paul, Method, apparatus and system for rapid and sensitive standoff detection of surface contaminants.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.