Quantitative cavity-enhanced photothermal dynamics in TMDC-integrated ultrahigh-Q microcavities

TL;DR

This study quantitatively analyzes photothermal effects in TMDC monolayers integrated with ultrahigh-Q microcavities, demonstrating controlled heating, PL modulation, and selective excitonic coupling for all-optical thermal control.

Contribution

It introduces a quantitative framework combining a temperature-dependent bandgap model with microcavity thermo-optic response to understand photothermal effects in TMDC-microcavity systems.

Findings

Redshift of PL peak energy with pump tuning across resonance

Spectral and temporal differences in fiber-collected PL versus free-space emission

Estimated local temperature rise from the combined model

Abstract

We investigate photothermal effects in monolayer transition metal dichalcogenides (TMDCs) integrated with an ultrahigh-Q silica microcavity. Launching a continuous-wave laser into a cavity resonance enables controlled intracavity heating, allowing direct observation of excitonic photoluminescence (PL) modulation. A distinct redshift of the PL peak energy is observed as the pump wavelength is tuned across resonance. This behavior is quantitatively reproduced by a temperature-dependent bandgap model that combines the Varshni relation with the thermo-optic response of the microcavity, from which the local temperature rise can be estimated. We further find that PL collected through a fiber waveguide exhibits spectral and temporal characteristics markedly different from free-space emission, indicating selective coupling of the microcavity to specific excitonic channels. These results provide a quantitative framework for understanding photothermal effects in TMDC-microcavity hybrid systems and offer a versatile approach for all-optical control and probing of thermal states in integrated nanophotonic devices.