Reconstructive spectrometer using double-layer disordered metasurfaces
Dong-gu Lee, Gookho Song, Chunghyeong Lee, Chanseok Lee, Mooseok Jang
Abstract
Conventionally, optical spectrometers rely on traditional dispersive elements like grating and prism, which pose inherent challenges for miniaturizing spectrometers, including the trade-off between propagation distance and spectral resolution and calibration ambiguity. Here, we present a random dispersive element-double-layer disordered metasurfaces-where wavelength-specific speckle patterns can be uniquely determined a priori without ambiguity in wavelength and propagation distance. By directly mounting this element on an image sensor, we implement a spectrometer with a spectral resolution of around 1 nanometer and an operable range of 440 to 660 nanometers, comprising 221 spectral channels, within a form-factor of less than 1 centimeter. Our results firmly establish that the versatility of multilayer disordered metasurfaces in the spatio-spectral domain can be fully exploited for on-sensor spectroscopic applications.