Technological implementation of a photonic Bier-Glass cavity

TL;DR

This paper presents a novel quantum photonic device called the photonic Bier-Glass cavity, which combines broadband mode shaping with Purcell enhancement to improve entangled photon pair extraction.

Contribution

It introduces the design, fabrication, and optical characterization of a new GaAs-based photonic cavity integrating quantum dots for enhanced quantum light emission.

Findings

Broadband optical resonances confirmed

Amplified spontaneous emission observed

Device supports efficient entangled photon extraction

Abstract

In this paper, we introduce a novel quantum photonic device, which we term photonic Bier-Glass cavity. We discuss its fabrication and functionality, which is based on the coupling of integrated In(Ga)As quantum dots to a broadband photonic cavity resonance. By design, the device architecture uniquely combines the Purcell enhancement of a photonic micropillar structure with broadband photonic mode shaping of a vertical, tapered waveguide, making it an interesting candidate to enable the efficient extraction of entangled photon pairs. We detail the epitaxial growth of the heterostructure and the necessary lithography steps to approach a GaAs-based photonic device with a height exceeding 15 $\mu$m, supported on a pedestal that can be as thin as 20 nm. We present an optical characterization, which confirms the presence of broadband optical resonances, in conjunction with amplified spontaneous emission of single photons.