Optical spectroscopy is a versatile characterization technique for a wide range of applications. Developing miniaturized spectrometers is the trend for applications in which small footprint takes precedence over high resolution. However, development of micro-spectrometers based on miniaturized or integrated optics is approaching a bottleneck toward submillimeter scales because of the inherent scale limitation of their optical components or path lengths. Although these constraints can be circumvented with computational spectral reconstruction by addressing a full range of spectral components simultaneously at multiple detectors, complex millimeter-scale arrays of individually prepared filters arranged over charge-coupled device or complementary metal-oxide semiconductor detectors are difficult to be miniaturized.