| 摘要 |
<p>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 (e.g., between = 1.3 m and = 6.5 m for silicon and = 1.3 m and = 12.0 m for germanium), to probe the absorption spectrum of the fluid surrounding the waveguide. Launching a mid-IR beam into the waveguide exposed to a particular analyte causes attenuation of the evanescent waves spectral components due to absorption by carbon, oxygen, hydrogen, and/or nitrogen bonds in the surrounding fluid. Detecting these changes at the waveguides 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.</p> |
