Excitonic Emission of Monolayer Semiconductors Near-Field Coupled to High-Q Microresonators.

Javerzac-Galy, Clément; Kumar, Anshuman; Schilling, Ryan D; Piro, Nicolas; Khorasani, Sina; Barbone, Matteo; Goykhman, Ilya; Khurgin, Jacob B et al. · Nano Lett · 2018

basic_science · Level V

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Abstract

We present quantum yield measurements of single layer WSe<sub>2</sub> (1L-WSe<sub>2</sub>) integrated with high-Q ( Q > 10<sup>6</sup>) optical microdisk cavities, using an efficient (η > 90%) near-field coupling scheme based on a tapered optical fiber. Coupling of the excitonic emission is achieved by placing 1L-WSe<sub>2</sub> in the evanescent cavity field. This preserves the microresonator high intrinsic quality factor ( Q > 10<sup>6</sup>) below the bandgap of 1L-WSe<sub>2</sub>. The cavity quantum yield is QY<sub>c</sub> ≈ 10<sup>-3</sup>, consistent with operation in the broad emitter regime (i.e., the emission lifetime of 1L-WSe<sub>2</sub> is significantly shorter than the bare cavity decay time). This scheme can serve as a precise measurement tool for the excitonic emission of layered materials into cavity modes, for both in plane and out of plane excitation.