Waveguide-coupled deterministic quantum light sources and post-growth engineering methods for integrated quantum photonics

Integrated photonic quantum circuits (IPQCs) have attracted increasing attention in recent years due to their widespread applications in quantum information science. While the most envisioned quantum technologies such as quantum communications, quantum computer and quantum simulations have placed a strict constraint on the scalability of chip-integrated quantum light sources. By introducing size-confined nanostructures or crystal imperfections, low-dimensional semiconductors have been broadly explored as chip-scale deterministic single-photon sources (SPSs). Thus far a variety of chip-integrated deterministic SPSs have been investigated across both monolithic and hybrid photonic platforms, including molecules, quantum dots, color centers and two-dimensional materials. With the rapid development of the chip-scale generation of single photons with deterministic quantum emitters, the field of IPQCs has raised new challenges and opportunities. In this paper, we highlight recent progress in the development of waveguide-coupled deterministic SPSs towards scalable IPQCs, and review the post-growth tuning techniques that are specifically developed to engineer the optical properties of these WG-coupled SPSs. Future prospects on stringent requirement for the quantum engineering toolbox in the burgeoning field of integrated photonics are also discussed.