Circularly-polarized light detection from achiral materials by optically programmable transient IR-induced chirality

Objective

Detection of circularly polarized light (CPL) currently relies on polarization-insensitive photodetectors combined with bulky chiral optics. This limits their sensitivity, scalability and integration into modern optoelectronic technologies. This project will establish a fundamentally new photonic route to enable CPL detection by achiral organic and perovskite materials through mid-infrared excitation of vibrational modes that transiently break local symmetry to induce chirality. This will be achieved through a novel spectroscopic method that uses a mid-IR pump pulse to drive symmetry-breaking vibrational modes, inducing transient chirality, followed by a circularly-polarized probe to generate photocurrent, thereby enabling determination of the photocurrent dissymmetry factor, which measures a photodetector’s ability to distinguish left- and right-handed CPL. The major objective is to demonstrate non-zero dissymmetry factors from achiral materials for the first time via this photonic approach. Subsequently, by mapping the dissymmetry factor across a library of organic and perovskite single crystals, the project will identify the key structure-property relationships that enable sensitive CPL photodetection from achiral materials to engineer the best-performing devices. The implementation of this proposal will exceed state-of-the-art photodetection technology and align with EU priorities in photonics, quantum technologies and advanced materials, while delivering transferable expertise and practical skills in spectroscopy and device engineering, propelling my trajectory toward independence. Demonstrating achiral CPL detectors and developing the novel spectroscopic method used to test them will expand our fundamental understanding of the role of chirality in light-matter interactions while also laying the foundations for lightweight, solution processable, low-cost and integrable CPL photodetectors for quantum information, sensing, security and optical communication.