A silicon based surface micro-machined distributed Bragg reflector for MEMS spectroscopic applications

While optical spectral analysis has shown great promise in industrial and agricultural applications, the cost, size, and fragility of spectrometer instruments have hindered widespread application of the technology. MEMS microspectrometers offer great hope for low-cost, light-weight, robust, spectrometers, paving the way for pervasive use of infrared spectroscopy in agriculture. In the past, germanium based microspectrometers have been successfully demonstrated in the shortwave infrared and midwave infrared spectral ranges. How-ever, high absorption in the germanium has prevented operation of these microspectrometers in the near-infrared and visible wavelengths. We present here a silicon based surface micro-machined distributed Bragg reflector, for short wave infrared wavelengths, suited to MEMS spectrometer fabrication, with near ideal reflectance properties.