  Miniaturized spectrometers are widely used for non-destructive and on-field
spectral analysis. Here we report a tunable grating-based MEMS spectrometer for
visible to near-infrared (VIS-NIR) spectroscopy. The MEMS spectrometer consists
of a spherical mirror and an electrothermally actuated tunable grating. The
spectrometer detects the dispersed spectral signal with a single-pixel detector
by tilting the diffraction grating. The large tilting angle from electrothermal
actuation and highly dispersive diffraction grating improves the spectral range
and resolution, respectively. The MEMS spectrometer was fully packaged within
1.7 cm3 and provides a measurable spectral range up to 800 nm with an average
1.96 nm spectral resolution. This miniaturized single-pixel spectrometer can
provide diverse applications for advanced mobile spectral analysis in
agricultural, industrial, or medical fields.
