An adaptive moiré sensor for spectro-polarimetric hyperimaging

Abstract

Moiré photonic structures permit the engineering of optical band structures and light–matter interactions, offering new opportunities in photonics and optoelectronics, paving the way for new nanophotonic applications such as ultra-low threshold lasing, and versatile nonlinear and quantum light sources; however, the lack of in situ tunability has limited the potential of these structures until now. For example, the lack of control of the twist angle is an obstacle to high-resolution material spectroscopy and the development of new applications that require moiré optical properties. Here we present a microelectromechanical system (MEMS)-integrated twisted moiré photonic crystal sensor with a tunable interlayer distance and twist angle. The MEMS actuators modulate the wavelength and polarization resonances of the photonic crystal sensor via a twist- and gap-tuned moiré scattering effect. Using a reconstruction algorithm, this chip-based sensor can be used to simultaneously resolve the spectrum and polarization state of a wide-band signal in the telecommunications range and the full Poincaré sphere. We also demonstrate hyperspectral and hyperpolarimetric imaging using this single sensor. Our research illustrates some of the remarkable applications of multidimensional control of degrees of freedom in twisted moiré photonic platforms and establishes a scalable pathway towards creating comprehensive flat-optics devices suitable for versatile light manipulation and information processing. By integrating a moiré photonic structure on-chip with advanced microelectromechanical system (MEMS) technology, an in situ twisted moiré photonic platform that can be tuned is realized, enabling nanometre-scale positioning of two optical nanostructures in either the near- or far-field coupling regime.