Quantum emitters are widely used in quantum networks, quantum information processing, and quantum sensing due to their excellent optical properties. Compared with Stokes excitation, quantum emitters under anti-Stokes excitation exhibit better performance. In addition to laser cooling and nanoscale thermometry, anti-Stokes excitation can improve the coherence of single-photon sources for advanced quantum technologies. In this review, we follow the recent advances in phonon-assisted upconversion photoluminescence of quantum emitters and discuss the upconversion mechanisms, applications, and prospects for quantum emitters with anti-Stokes excitation.Quantum emitters are widely used in quantum networks, quantum information processing, and quantum sensing due to their excellent optical properties. Compared with Stokes excitation, quantum emitters under anti-Stokes excitation exhibit better performance. In addition to laser cooling and nanoscale thermometry, anti-Stokes excitation can improve the coherence of single-photon sources for advanced quantum technologies. In this review, we follow the recent advances in phonon-assisted upconversion photoluminescence of quantum emitters and discuss the upconversion mechanisms, applications, and prospects for quantum emitters with anti-Stokes excitation.

Epitaxial quantum dots formed by III–V compound semiconductors are excellent sources of non-classical photons, creating single photons and entangled multi-photon states on demand. Their semiconductor nature allows for a straightforward combination with mature integrated photonic technologies, leading to novel functional devices at the single-photon level. Integrating a quantum dot into a carefully engineered photonic cavity enables control of the radiative decay rate using the Purcell effect and the realization of photon–photon nonlinear gates. In this review, we introduce the basis of epitaxial quantum dots and discuss their applications as non-classical light sources. We highlight two interfaces—one between flying photons and the quantum-dot dipole, and the other between the photons and the spin. We summarize the recent development of integrated photonics and reconfigurable devices that have been combined with quantum dots or are suitable for hybrid integration. Finally, we provide an outlook of employing quantum-dot platforms for practical applications in large-scale quantum computation and the quantum Internet.

Quantum efficiency is a critical piece of information of a quantum emitter and regulates the emitter’s fluorescence decay dynamics in an optical environment through the Purcell effect. Here, we present a simple way to experimentally probe fluorescence quantum efficiency of single dibenzoterrylene molecules embedded in a thin anthracene microcrystal obtained through a co-sublimation process. In particular, we correlate the fluorescence lifetime change of single dibenzoterrylene molecules with the variation of the matrix thickness due to natural sublimation. With the identification of the molecule emission dipole orientation, we could deduce the near-unity intrinsic quantum efficiency of dibenzoterrylene molecules in the anthracene matrix.

多年来，硅和锗一直被认为是合适制造探测器和集成光电器件的半导体材料。然而，与金刚石基器件相比，这种四价半导体的抗辐射损伤能力较差，而且在恶劣条件或高强光辐照下，器件的稳定性较差。近年来，金刚石因其优异的光学与力学性能，在集成光子学、传感和量子光学等领域展现了巨大的应用前景。利用激光诱导金刚石微纳结构为开发金刚石上的三维光互联器件、全碳探测器、石墨电阻以及单光子源的实现提供了一种有潜力的制备方法。阐述了飞秒激光诱导金刚石色心形成、石墨化和折射率变化的物理机制，在此基础上，进一步探究了飞秒激光诱导金刚石微纳结构在单光子源、传感器和光波导等方面的应用，并对未来发展趋势进行了展望。