New interferometric photon-correlation tools for spectral diffusion measurements of emerging single-photon emitters

Spectral diffusion is a ubiquitous process caused by bath fluctuations which randomizes the spectral mode of single-photon emitters at cryogenic temperatures. Accurately measuring spectral diffusion on a single-emitter level is still a challenging task owing to the required high spectral and temporal resolution with an additionally high temporal dynamic range. In this talk, I highlight our recent progress towards understanding spectral diffusion in nascent quantum emitters using photon-correlation Fourier spectroscopy (PCFS). PCFS can measure the bandwidth and kinetics of spectral fluctuations down to nanosecond timescales. Using PCFS, I show how quantum emitters in 2D hexagonal boron nitride exhibit multi-timescale discrete spectral jumping that can be attributed to a bath with at least two characteristic fluctuation relaxation time constants.Broadly, I propose PCFS as a particularly suitable tool for the detailed study of decoherence processes and spectral diffusion.