Polariton lasing in Mie-resonant perovskite nanocavity

TL;DR

This paper demonstrates a deeply subwavelength polariton nanolaser using a CsPbBr3 nanocavity that achieves coherent visible emission through exciton-polariton condensation on Mie resonances, enabling compact on-chip applications.

Contribution

It introduces a novel polariton nanolaser based on Mie resonances in a CsPbBr3 nanoparticle, achieving subwavelength lasing with detailed analysis of condensation mechanisms.

Findings

Achieved coherent emission at 0.53 μm from a 0.007 μm³ nanocavity.

Proved polaritonic nature through comparison with waveguiding systems.

Enabled by high exciton binding energy and optimized polariton condensation.

Abstract

Deeply subwavelength lasers (or nanolasers) are highly demanded for compact on-chip bioimaging and sensing at the nanoscale. One of the main obstacles for the development of single-particle nanolasers with all three dimensions shorter than the emitting wavelength in the visible range is the high lasing thresholds and the resulting overheating. Here we exploit exciton-polariton condensation and mirror-image Mie modes in a cuboid CsPbBr$_3$ nanoparticle to achieve coherent emission at the visible wavelength of around 0.53~$\mu $m from its ultra-small ($\approx$0.007$\mu$m$^3$ or $\approx\lambda^3$/20) semiconductor nanocavity. The polaritonic nature of the emission from the nanocavity localized in all three dimensions is proven by direct comparison with corresponding one-dimensional and two-dimensional waveguiding systems with similar material parameters. Such a deeply subwavelength nanolaser is enabled not only by the high values for exciton binding energy ($\approx$35 meV), refractive index ($>$2.5 at low temperature), and luminescence quantum yield of CsPbBr$_3$, but also by the optimization of polaritons condensation on the Mie resonances. Moreover, the key parameters for optimal lasing conditions are intermode free spectral range and phonons spectrum in CsPbBr$_3$, which govern polaritons condensation path. Such chemically synthesized colloidal CsPbBr$_3$ nanolasers can be easily deposited on arbitrary surfaces, which makes them a versatile tool for integration with various on-chip systems.