Office of Technology Transfer – University of Michigan

A Composite Fabry-Perot Cavity Sensor

Technology #5230

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Xudong Fan
Managed By
Bryce Pilz
Director Licensing 734-615-8433
Patent Protection
US Patent Pending

Vapor Detection

Vapor detection is a method used to identify particles in an unknown sample. The market for vapor detection is vast due to the multitude of applications and industries that use the technology. The current standard for detection is a Gas-Chromatography instrument. The technology has been in use for over 100 years and although has relatively rapid detection rates it has limitations in the ability to identify low volume particles. This is especially true of micro-Gas Chromatography instruments mostly used for specialized applications requiring rapid detection with potentially low volume samples. However most of these detection instruments are notorious for limited analyte detection, slow detection rates, and relatively poor accuracy. There is a need for a sensor that can improve the performance of micro-Gas Chromatography with results and capabilities on par with conventional Gas Chromatography devices.

A Sensor to Drastically Improve Vapor Detection in Micro-Gas Chromatography

A versatile, self-referenced composite Fabry-Perot Sensor has been developed that can rapidly and precisely measure analyte vapors. Due to the sensor’s ability to self-reference, changes in thickness and refractive index of the polymer layer can be detected. This allows for accurate vapor quantitation regardless of the polymer thickness, refractive index, and light incident angle and wavelength. The sensor is capable of vapor detection on the order of a few pico-grams. The sensor is also highly compatible with micro-gas chromatography instruments.

Applications and Advantages


  • On-column sensing in micro-gas Chromatography
  • Photo-acoustic imaging


  • Precise and quantitative measurement of vapor analyte
  • Sensor is independent of inconsistent polymer thicknesses due to fabrication process
  • Highly compatible with microfluidics for rapid, on-line, non-invasive, non-destructive measurement
  • Can be fabricated in an array format for imaging applications