Microspectrometer based on a tunable fabry-perot interferometer and microsphere cavities
AssigneeTanner Research, Inc.
InventorRavi Kant Verma
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Abstract
The present invention is a cost-effective and compact micro-spectrometer for rapid detection of chemical compounds in the low concentration limit. The invention provides for significantly higher sensitivity compared to conventional spectroscopy techniques (continuous wave and Fourier transform methods) by placing the sample within a high Finesse etalon cavity. An Optical Spectrum Analyzer (OSA) built on either continuous wave (CW-SPEC), or Fourier Transform Absorption Spectroscopy (FT-SPEC) is used to monitor the spectrum from the etalon cavity/sample combination during tuning of the etalon cavity˜this information is then used to reconstruct the absorption spectrum.
Claims18
An absorption spectrometer, comprising:
- an absorption signal generator comprising a cavity for receiving a sample, wherein an input optical beam traverses a multi-bounce optical path across said sample from an input of said cavity to an output of said cavity;
- and
- an optical spectrum analyzer coupled to the output of said cavity for measuring intensity of said cavity output as a function of wavelength.
A method for performing absorption spectroscopy, comprising:
- receiving a sample having a wavelength dependent transmission coefficient within an cavity having a multi-bounce optical path between a cavity input and a cavity output;
- traversing an optical beam across said sample along the multi-bounce optical path;
- and
- measuring intensity of cavity output as a function of wavelength.
An absorption spectrometer, comprising:
- an absorption signal generator comprising a microsphere cavity for receiving a sample and a tuning device for varying a length of a multi-bounce optical path traversed by an input optical beam from an input of said cavity to an output of said cavity to scan one of a plurality of periodic intensity peaks in transmission spectrum of said absorption signal generator across an absorption band of said sample;
- and
- an optical spectrum analyzer coupled to the output of said cavity for measuring intensity of said cavity output as a function of wavelength.
Dependencies are inferred from the claim text.