Integrated tunable optical sensor (ITOS) system

• US 20040169854A1
• Filed: 02/28/2003
• Published: 09/02/2004
• Est. Priority Date: 02/28/2003
• Status: Active Grant

• Current Assignee: UT-Battelle LLC
• Original Assignee: UT-Battelle LLC
• Inventors: Vo-Dinh, Tuan, Wintenberg, Alan
• Granted Patent: US 6,965,431 B2
• Time in Patent Office: Days
• US Class Current: 356/301
• CPC Class Codes: G01J 3/1256 using acousto-optic tunable filter; acousto-optic elements or systems G02F1/11, G02F1/33
• CPC Class Codes: G01J 3/2889 Rapid scan spectrometers; Time resolved spectrometry
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 2021/656 Raman microprobe
• CPC Class Codes: G01N 21/65 Raman scattering
• CPC Class Codes: G01N 21/658 enhancement Raman, e.g. surface plasmons

Abstract

A scanning tunable detection system and related method for analyzing samples includes a source of time varying excitation signals and a tunable optical filter for selectively transmitting time-varying optical signals emanated from a sample following irradiation with the time varying excitation signals. A detector is provided for converting the time-varying optical signals to electrical detection signals. The system can identify components in a sample using phase sensitive or time sensitive detection. A slew scan mode can be used to permit slow scanning through spectral regions rich in information but quickly in regions without such information.

Claims

1. A scanning tunable detection system for analyzing a sample, comprising:

a source of time varying excitation signals;

a tunable optical filter for selectively transmitting time-varying optical signals emanated from said sample following irradiation with said time varying excitation signals, and

a detector for converting said time-varying optical signals to electrical detection signals.

2. The system of claim 1, wherein said tunable optical filter comprises an AOTF or a LCTF.

3. The system of claim 2, further comprising structure for modulating scanning of said AOTF.

4. The system of claim 1, further comprising a data treatment system for receiving said detection signals, said data treatment system providing at least one of phase-sensitive and time-sensitive detection.

5. The system of claim 1, further comprising diffractive optics for dividing a beam from said source of time varying excitation signal into a plurality of discrete excitation light beams which irradiate a plurality of locations on said sample, wherein said detector comprises a detector array including a plurality of pixels for receiving a plurality of said time-varying optical signals emanated from said locations on said sample.

6. The system of claim 1, wherein said detector comprises at least one avalanche photodiode.

7. The system of claim 1, wherein said time-varying optical signals comprise Raman signals.

8. The system of claim 1, wherein said time-varying optical signals fluorescence signals, phosphorescence signals, and atomic emission signals.

9. The system of claim 1, further comprising a gated integrator for receiving said detection signals or signals derived from said detection signals, said gated integrator integrating said detection signals only after a predetermined period of time after said sample irradiation has ceased.

10. The system of claim 9, wherein a train of pulses are used to modulate said source of excitation signals, said train of pulses also applied to said gated integrator after said predetermined period of time.

11. The system of claim 1, further comprising a synchronous demodulator for receiving said time-varying electrical signals and a phase shift selector, wherein said phase shift selector synchronizes said synchronous demodulator to a modulation frequency applied to said excitation source.

12. The system of claim 1, further comprising a synchronous demodulator for receiving said time-varying electrical signals and a phase shift selector, wherein said phase shift selector synchronizes said synchronous demodulator to a modulation frequency applied to an output of said excitation source.

13. The system of claim 1, wherein said time varying excitation signals comprise a pulse train and said emanated signal is a series of pulses, further comprising a multiplexer for collecting said series of pulses and a first and second counter synchronized with said pulse train, said first counter for processing “

0”

states in said detection signals and said second counter for processing “

1”

states in said detection signals.

14. The system of claim 13, further comprising a data collection and averaging module connected to outputs of both said first and said second counter.

15. The system of claim 1, further comprising structure for wirelessly transmitting said detection signals.

16. A method for identifying at least one component in a sample, comprising the steps of:

providing a source of time-varying radiation;

irradiating said sample with said time-varying radiation, wherein a time-varying optical signal emanates from said sample;

converting said time-varying optical signals to electrical detection signals, and

processing said electrical detection signals to provide time-varying measurements relating to said sample.

17. The method of claim 16, further comprising the step of selectively transmitting time-varying optical signals emanating from said sample.

18. The method of claim 17, wherein an AOTF or a LCTF provides said selective transmitting.

19. The method of claim 16, wherein said time varying measurements include lifetime determination.

20. The method of claim 19, wherein said time-varying measurements include time resolved measurements.

21. The method of claim 19, wherein said time-varying measurements include phase resolved measurements.

22. The method of claim 16, wherein said irradiation step comprises slew scanning.

23. The method of claim 16, wherein said optical signals comprises Raman signals.

24. The method of claim 16, further comprising the step of delaying initiation of said converting step for a predetermined time after said irradiating.

25. The method of claim 16, wherein said time-varying source provides a modulated frequency output, further comprising the step of synchronizing demodulation of said time-varying electrical signals with said modulated frequency.

26. The method of claim 16, wherein said processing comprises imaging said sample.