Circularly polarized lasing from chiral metal-organic frameworks

Abstract

Circularly polarized lasers play a pivotal role in classical optics, nanophotonics, and quantum optical information processing, while their fabrication remains complex. This article begins with examining the interactions between stimulated emission and chiral matter, outlining a simple strategy for producing circularly polarized lasing from chiral metal-organic frameworks (MOFs), such as the zeolitic imidazolate framework (ZIF), embedded with achiral laser dyes (L/D-ZIF⊃dyes). It is found that the stimulated emission threshold and intensity are influenced by the interplay between the chiral polarization of the pump light and the inherent chirality of the MOF nanoparticles. We further present the design of a chiral vertical-cavity surface-emitting laser (VCSEL), comprising an L/D-ZIF⊃dyes solid-state film sandwiched between a high-reflectivity distributed Bragg reflector (DBR) mirror and a silver film. The cavity-based lasing exhibits higher asymmetry between emitting left-handed and right-handed polarized light compared to chiral spontaneous emission (SE) and amplified spontaneous emission (ASE), with an asymmetry value g lum of approximately ±0.31. This value is nearly four-fold greater than that of SE and twice that of ASE. Our findings reveal a new approach to amplify chiral signals, promoting the comprehension and application of chiral–matter interactions, and offering a simple yet effective strategy to fabricate chiral lasers.