Purcell enhancement of erbium ions in TiO$_{2}$ on silicon nanocavities

TL;DR

This paper demonstrates a scalable, CMOS-compatible platform using erbium-doped TiO₂ on silicon to enhance telecom photon emission via nanocavities, advancing quantum memory development.

Contribution

It introduces a new scalable approach with erbium-doped TiO₂ films on silicon, achieving high-Q nanocavities and Purcell enhancement for telecom quantum emitters.

Findings

Achieved quality factors over 5×10⁴ in photonic crystal cavities.

Realized Purcell-enhanced emission rates exceeding 200.

Demonstrated a CMOS-compatible platform for telecom quantum memories.

Abstract

Isolated solid-state atomic defects with telecom optical transitions are ideal quantum photon emitters and spin qubits for applications in long-distance quantum communication networks. Prototypical telecom defects such as erbium suffer from poor photon emission rates, requiring photonic enhancement using resonant optical cavities. Many of the traditional hosts for erbium ions are not amenable to direct incorporation with existing integrated photonics platforms, limiting scalable fabrication of qubit-based devices. Here we present a scalable approach towards CMOS-compatible telecom qubits by using erbium-doped titanium dioxide thin films grown atop silicon-on-insulator substrates. From this heterostructure, we have fabricated one-dimensional photonic crystal cavities demonstrating quality factors in excess of $5\times10^{4}$ and corresponding Purcell-enhanced optical emission rates of the erbium ensembles in excess of 200. This easily fabricated materials platform represents an important step towards realizing telecom quantum memories in a scalable qubit architecture compatible with mature silicon technologies.