MULTIPLEX TUNABLE FILTER SPECTROMETER

• US 20100290045A1
• Filed: 04/07/2010
• Published: 11/18/2010
• Est. Priority Date: 07/30/2008
• Status: Active Grant

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: Precisive, LLC (MKS Instruments Incorporated)
• Inventors: Saptari, Vidi A.
• Granted Patent: US 8,896,839 B2
• Time in Patent Office: Days
• US Class Current: 356/326
• CPC Class Codes: G01J 2003/1247 Tuning
• CPC Class Codes: G01J 3/06 Scanning arrangements arrangements for order-selection
• CPC Class Codes: G01J 3/32 Investigating bands of a spectrum in sequence by a single detector
• CPC Class Codes: G01N 2021/3174 Filter wheel
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427
• CPC Class Codes: G01N 21/33 using ultraviolet light G01N21/39 takes precedence
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 2201/129 Using chemometrical methods

Abstract

The invention provides spectroscopic systems and spectrometers employing an optical interference filter module having a plurality of bandpass regions. In certain embodiments, the systems include a mechanism for wavelength tuning/scanning and wavelength band decoding based on an angular motion of one or more filters. A spectral processing algorithm separates the multiplexed wavelength-scanned bandpass regions and quantifies the concentrations of the analyzed chemical and/or biological species. The spectroscopic system allows for compact, multi-compound analysis, employing a single-element detector for maximum performance-to-cost ratio. The spectroscopic system also allows for high-sensitivity measurement and robust interference compensation.

Claims

1. A spectroscopic system comprising:

an optical filter module comprising one or more optical interference filters configured to receive electromagnetic radiation from an electromagnetic radiation source, the one or more filters comprising a plurality of multiplexed bandpass regions configured to simultaneously transmit multiple wavelength bands of electromagnetic radiation through the filter module; and

an optical detector configured to receive the multiple wavelength bands of electromagnetic radiation transmitted through the filter module and to generate one or more electrical signals indicative of electromagnetic radiation intensity as a function of wavelength.

2. The spectroscopic system of claim 1, wherein the filter module comprises an interference filter comprising multiple bandpass regions.

3. The spectroscopic system of claim 1, wherein the filter module comprises a plurality of interference filters which individually or collectively comprise multiple bandpass regions.

4. The spectroscopic system of claim 1, wherein the optical filter module is configured to provide adjustment of the incident angle of the electromagnetic radiation from the electromagnetic radiation source onto the one or more optical filters.

5. The spectroscopic system of claim 4, wherein the optical filter module comprises a rotatable filter assembly to provide the incident angle adjustment.

6. The spectroscopic system of claim 5, wherein the rotatable filter assembly comprises a position detector to produce at least a first signal comprising a series of digital pulses corresponding to the angular position of the rotatable filter assembly.

7. The spectroscopic system of claim 6, wherein the position detector is configured to clock analog-to-digital conversion.

8. The spectroscopic system of claim 1, further comprising:

a memory for storing code that defines a set of instructions; and

a processor for executing the set of instructions to identify one or more species present in a sample from which the electromagnetic radiation emanates or through which the electromagnetic radiation passes prior to reception by the optical detector.

9. The spectroscopic system of claim 8, wherein the processor is configured to execute the set of instructions to process data corresponding to the electromagnetic radiation intensity measured by the detector over the multiple wavelength bands, thereby identifying one or more species present in the sample.

10. The spectroscopic system of claim 8, wherein the processor is configured to execute the set of instructions to process data corresponding to the electromagnetic radiation intensity measured by the detector over the multiple wavelength bands, thereby quantifying each of one or more species present in the sample.

11. The spectroscopic system of claim 1, wherein the optical detector is configured to receive the multiple wavelength bands of electromagnetic radiation after transmission through both the filter module and a sample being measured.

12. The spectroscopic system of claim 1, further comprising a sample cell configured to contain a sample through which the electromagnetic radiation passes or from which the electromagnetic radiation emanates prior to reception by the optical detector.

13. The spectroscopic system of claim 12, wherein the sample cell is located upstream of the optical filter module.

14. The spectroscopic system of claim 12, wherein the sample cell is located downstream of the optical filter module.

15. The spectroscopic system of claim 1, wherein the optical detector, in conjunction with the optical filter module, is configured to generate one or more electrical signals indicative of electromagnetic radiation intensity over a sweep of wavelengths within each of the multiple wavelength bands.

16. The spectroscopic system of claim 5, wherein the rotatable filter assembly comprises at least four multiplexed bandpass regions on a single rotatable filter assembly with a single rotation axis.

17. The spectroscopic system of claim 1, further comprising the electromagnetic radiation source.

18. The spectroscopic system of claim 17, wherein the electromagnetic radiation source is a producer of at least one member selected from the group consisting of visible light, infrared light, and ultraviolet light.

19. A spectroscopic method for detecting and/or quantifying one or more species in a sample, the method comprising the steps of:

directing electromagnetic radiation from an electromagnetic radiation source into an optical filter module comprising one or more optical interference filters, the one or more optical filters comprising a plurality of multiplexed bandpass regions configured to transmit multiple wavelength bands of electromagnetic radiation through the filter module simultaneously;

directing the multiple wavelength bands of electromagnetic radiation through a sample comprising one or more species;

directing the multiple wavelength bands of electromagnetic radiation from the sample into an optical detector configured to generate one or more electrical signals indicative of electromagnetic radiation intensity over a sweep of wavelengths within each of the multiple wavelength bands; and

processing data corresponding to the one or more electrical signals to identify and/or quantify one or more species present in the sample.