Methods and apparatus for mid-infrared sensing
US9046650B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 11, 2013 |
| Grant date | Jun 2, 2015 |
| Priority date | — |
| Expiry date | Nov 11, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/122
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A chip-scale, air-clad semiconductor pedestal waveguide can be used as a mid-infrared (mid-IR) sensor capable of in situ monitoring of organic solvents and other analytes. The sensor uses evanescent coupling from a silicon or germanium waveguide, which is highly transparent in the mid-IR portion of the electromagnetic spectrum, to probe the absorption spectrum of fluid surrounding the waveguide. Launching a mid-IR beam into the waveguide exposed to a particular analyte causes attenuation of the evanescent wave's spectral components due to absorption by carbon, oxygen, hydrogen, and/or nitrogen bonds in the surrounding fluid. Detecting these changes at the waveguide's output provides an indication of the type and concentration of one or more compounds in the surrounding fluid. If desired, the sensor may be integrated onto a silicon substrate with a mid-IR light source and a mid-IR detector to form a chip-based spectrometer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.