# Pulse-Enhanced Two-Photon Interference with Solid State Quantum Emitters

## TL;DR

This paper demonstrates that applying a periodic sequence of $C0$ pulses can significantly improve two-photon interference and photon indistinguishability between solid-state quantum emitters affected by spectral diffusion, advancing scalable quantum networks.

## Contribution

The study introduces a control protocol using periodic $C0$ pulses to enhance two-photon interference in quantum emitters with spectral diffusion, a novel approach for solid-state quantum systems.

## Key findings

- Pulse sequence improves photon indistinguishability despite spectral diffusion.
- Enhanced two-photon interference observed with external control protocols.
- Spectral overlap issues mitigated by periodic pulsing in quantum emitters.

## Abstract

The ability to entangle distant quantum nodes is essential for the construction of quantum networks and for quantum information processing. For solid-state quantum emitters used as qubits, it can be achieved by photon interference. When the emitter is subject to spectral diffusion, this process can become highly inefficient, impeding the achievement of scalable quantum technologies. We study two-photon interference in the context of a Hong-Ou-Mandel (HOM)-type experiment for two separate quantum emitters, with different detunings with respect to a specific target frequency. We evaluate the second order coherences that characterize photon indistinguishability between the two emitters. We find that the two-photon interference operation that is inefficient in the absence of a control protocol, when the two detunings are different and spectral overlap is lessened, can be highly improved by a periodic sequence of $\pi$ pulses at a set target frequency. Photon indistinguishability in solid state and other quantum emitters subject to spectral diffusion can thus be enhanced by the proposed pulse sequence and similar external control protocols despite the fluctuations in the environment.