Scalable in operando strain tuning in nanophotonic waveguides enabling three-quantum dot superradiance

TL;DR

This paper presents a scalable method for in operando strain tuning of quantum dots in nanophotonic waveguides, enabling the demonstration of three-quantum dot superradiance by selectively tuning their emission energies.

Contribution

It introduces a novel in operando laser crystallization technique to precisely tune individual quantum dots within a photonic structure, overcoming previous scalability limitations.

Findings

Quantum dots can be tuned over the full inhomogeneous distribution.

Multiple quantum dots can be brought into resonance within the same waveguide.

Demonstration of superradiant emission from three quantum dots.

Abstract

The quest for an integrated quantum optics platform has motivated the field of semiconductor quantum dot research for two decades. Demonstrations of quantum light sources, single photon switches, transistors, and spin-photon interfaces have become very advanced. Yet the fundamental problem that every quantum dot is different prevents integration and scaling beyond a few quantum dots. Here, we address this challenge by patterning strain via local phase transitions to selectively tune individual quantum dots that are embedded in a photonic architecture. The patterning is implemented with in operando laser crystallization of a thin HfO$_{2}$ film "sheath" on the surface of a GaAs waveguide. Using this approach, we tune InAs quantum dot emission energies over the full inhomogeneous distribution with a step size down to the homogeneous linewidth and a spatial resolution better than 1 $\mu $m. Using these capabilities, we tune multiple quantum dots into resonance within the same waveguide and demonstrate a quantum interaction via superradiant emission from three quantum dots.