Broadband transient full-Stokes luminescence spectroscopy.

Reponen, Antti-Pekka M; Mattes, Marcel; VanOrman, Zachary A; Estaque, Lilian; Pieters, Grégory; Feldmann, Sascha · Nature · 2025

basic_science · Level V

Where this comes from

Abstract

Materials emitting circularly polarized light (CPL) are highly sought after for applications ranging from efficient displays to quantum information technologies<sup>1-7</sup>. However, established methods for time-resolved CPL (TRCPL) characterization have notable limitations<sup>8-17</sup>, generally requiring a compromise between sensitivity, accessible timescales and spectral information. This has limited the acquisition of in-depth photophysical insight necessary for materials development. Here we demonstrate a high-sensitivity (noise level of the order of 10<sup>-4</sup>), broadband (about 400-900 nm), transient (nanosecond resolution, millisecond range) full-Stokes (CPL and linear polarizations) spectroscopy setup. The achieved combination of high-sensitivity, broad wavelength response and flexible time ranges represents a substantial advancement over previous TRCPL approaches. As a result, TRCPL measurements are shown to be applicable to hitherto inaccessible material systems and photophysical processes, including systems with low (10<sup>-3</sup>) dissymmetry factors and luminescence pathways spanning nanosecond to millisecond time ranges. Finally, full-Stokes measurements allow tracking the temporal evolution of linear polarization components, of interest by themselves, but especially relevant in the context of controlling for associated CPL artefacts<sup>18,19</sup> in the time domain.