Design and performance study of narrowband polarized colloidal quantum dots photodetector

Abstract Colloidal quantum dot-based (CQD) photodetectors have shown exceptional potential for low-cost, room-temperature broadband imaging. However, the isotropic optical properties of the CQD absorber hinder the capability for multi-dimensional photodetection, such as polarization. Here, we design and theoretically study a CQD photodetector with an encapsulation layer and metal grating layer, which can achieve narrowband polarization sensitivity with a full width at half maximum of 230 nm at a wavelength of 2 μ m. We first investigate the effect of the geometric parameters of the architecture. Moreover, we examine the broadband polarized optical properties and analyze the corresponding mechanisms. A large linear polarization ratio of 66 is obtained at an illuminated light wavelength of 2 μ m. These results contribute to offering a promising design for constructing narrowband polarized CQD photodetectors, particularly for quantum information processing in the realms of quantum communication and quantum cryptography.