All-silicon standing-wave microspectrometer with spectral resolution

A continuous resolution tuning from 72 nm to 6 nm is demonstrated with an all-silicon standing-wave microspectrometer. In the standing-wave spectrometer, incident light reflects off a micromirror, creating an optical standing wave that is continuously sampled by a partially-transmitting photodetector. The 13 × 13 mm Si device consists of a 2 × 2 mm reflective mirror pillar connected to four rectangular flexures. High-amplitude continuous harmonic motion is accomplished by driving with a DC-offset sinusoidal voltage at the mechanical resonance frequency. The detector is a Si p-i-n photodiode with transparent ZnO contacts. This microspectrometer offers real-time optimization of device sensitivity and system operating requirements.