Polariton Lasing in Micropillars With One Micrometer Diameter and Position-Dependent Spectroscopy of Polaritonic Molecules

TL;DR

This paper demonstrates polariton lasing in a 1-micron diameter micropillar, showing enhanced interactions and potential for quantum light applications, with site-selective excitation of polaritonic molecules.

Contribution

It reports the first polariton lasing in a sub-3-micron micropillar and introduces a geometrical decoupling method for excitation and collection.

Findings

Achieved polariton lasing in a 1-micron micropillar

Observed a significant blueshift indicating strong interactions

Demonstrated site-selective excitation of polaritonic molecules

Abstract

Microcavity polaritons are bosonic light-matter particles that can emit coherent radiation without electronic population inversion via bosonic scattering. This phenomenon, known as polariton lasing, strongly depends on the polaritons' confinement. Shrinking the polaritons' mode volume increases the interactions mediated by their excitonic part, and thereby the density-dependent blueshift of the polariton to a higher energy is enhanced. Previously, polariton lasing has been demonstrated in micropillars with diameters larger than three microns, in grating based cavities, fiber cavities and photonic crystal cavities. Here we show polariton lasing in a micropillar with one micron diameter operating in a single transverse mode that can be optimally coupled to a singlemode fiber. We geometrically decouple the excitation with an angle from the collection. From the number of collected photons we calculate the number of polaritons and observe a blueshift large enough to qualify our device for novel schemes of quantum light generation such as the unconventional photon blockade. To that end, we also apply angled excitation to polaritonic molecules and show site-selective excitation and collection of modes with various symmetries.