The realization of scalable, real world devices in quantum technologies requires myriad new approaches and hardware components. Integrated photonics play a crucial role in many applications in quantum information and quantum sensing, enabling the realization of key components such as new light sources, waveguides, resonators, and detectors. The field of integrated quantum photonics is booming, and an increasing number of research groups are contributing to the accelerating efforts to study fundamental and technological challenges at the intersection of quantum optics, nanophotonics, and hybrid integrated devices. This Special Topic Collection is dedicated to highlighting important progress in the field of integrated quantum photonics and presenting new cutting-edge results, both experimental and theoretical, toward the common goal of exploring quantum photonic phenomena.
The realization of scalable, real world devices in quantum technologies requires myriad new approaches and hardware components. Integrated photonics play a crucial role in many applications in quantum information and quantum sensing, enabling the realization of key components such as new light sources, waveguides, resonators, and detectors. The field of integrated quantum photonics is booming, and an increasing number of research groups are contributing to the accelerating efforts to study fundamental and technological challenges at the intersection of quantum optics, nanophotonics, and hybrid integrated devices. This Special Topic Collection is dedicated to highlighting important progress in the field of integrated quantum photonics and presenting new cutting-edge results, both experimental and theoretical, toward the common goal of exploring quantum photonic phenomena.
Photons are very promising resources for the whole field of quantum information processing. Bulk optics are currently not suitable for the realization of complex quantum optical schemes due to several drawbacks. The ongoing miniaturization of photonic structures due to the availability of sophisticated nanofabrication has provided huge opportunities for physical research of novel phenomena in nanophotonic systems and quantum technological applications. These include quantum information processing such as quantum computing, quantum communication, quantum metrology, and quantum sensing. Quantum communication is already quite advanced with several quantum key distribution (QKD) systems commercially available offering absolute security. Photonic quantum technologies are enabling breakthroughs in experimental tests of quantum physics and are close to practical applications of quantum technologies in imaging, secure communications, ultrasensitive metrology and quantum computing. There are several advantages to encoding a quantum bit onto a photon: the preparation and manipulation of single photons is easy, and the photonic qubit is a natural candidate for quantum imaging and communications. Furthermore, the qubit can be encoded in various degrees of freedom such as on the position, phase, time-bin, energy, angular momentum, polarization of the photon—or a combination of these. This flexibility leads to enormous opportunities for scientific exploration and in practical applications. This special issue on “Photonic Quantum Technologies” presents selected papers on photonic quantum systems from leading groups in the world. The articles represent a flavor of the cutting-edge research that is going on in this area. The studied material systems range from molecules to semiconductor quantum emitters. A major challenge is the design of telecom photon emitters with high efficiency, good yield, spectral purity, stability and the possibility of mass manufacture. We believe that this Special Issue will provide an overview of recent exciting developments in the field of photonic quantum technologies, serving to keep researchers up-to-date with the latest progress and spurring on new concepts in this field.
Abstract Integrated photonics will play a key role in quantum systems as they grow from few-qubit prototypes to tens of thousands of qubits. The underlying optical quantum technologies can only be realized through the integration of these components onto quantum photonic integrated circuits (QPICs) with accompanying electronics. In the last decade, remarkable advances in quantum photonic integration have enabled table-top experiments to be scaled down to prototype chips with improvements in efficiency, robustness, and key performance metrics. These advances have enabled integrated quantum photonic technologies combining up to 650 optical and electrical components onto a single chip that are capable of programmable quantum information processing, chip-to-chip networking, hybrid quantum system integration, and high-speed communications. In this roadmap article, we highlight the status, current and future challenges, and emerging technologies in several key research areas in integrated quantum photonics, including photonic platforms, quantum and classical light sources, quantum frequency conversion, integrated detectors, and applications in computing, communications, and sensing. With advances in materials, photonic design architectures, fabrication and integration processes, packaging, and testing and benchmarking, in the next decade we can expect a transition from single- and few-function prototypes to large-scale integration of multi-functional and reconfigurable devices that will have a transformative impact on quantum information science and engineering.
Integrated photonics will play a key role in quantum systems as they grow from few-qubit prototypes to tens of thousands of qubits. The underlying optical quantum technologies can only be realized through the integration of these components onto quantum photonic integrated circuits (QPICs) with accompanying electronics. In the last decade, remarkable advances in quantum photonic integration have enabled table-top experiments to be scaled down to prototype chips with improvements in efficiency, robustness, and key performance metrics. These advances have enabled integrated quantum photonic technologies combining up to 650 optical and electrical components onto a single chip that are capable of programmable quantum information processing, chip-to-chip networking, hybrid quantum system integration, and high-speed communications. In this roadmap article, we highlight the status, current and future challenges, and emerging technologies in several key research areas in integrated quantum photonics, including photonic platforms, quantum and classical light sources, quantum frequency conversion, integrated detectors, and applications in computing, communications, and sensing. With advances in materials, photonic design architectures, fabrication and integration processes, packaging, and testing and benchmarking, in the next decade we can expect a transition from single- and few-function prototypes to large-scale integration of multi-functional and reconfigurable devices that will have a transformative impact on quantum information science and engineering.
Quantum technologies promise a change of paradigm for many fields of application, for example in communication systems, in high-performance computing and simulation of quantum systems, as well as in sensor technology. However, the experimental realization of suitable system still poses considerable challenges. Current efforts in photonic quantum science target the implementation of practical devices and scalable systems, where the realization of quantum devices and controlled quantum network structures is key for envisioned future technologies. Here we present our progress on the engineering of integrated photonic systems, which can overcome current limitations for the realization of scalable photonic systems. Specifically, our research currently focuses on three different but complementary topics: integrated devices based on lithium niobate circuits, engineering and harnessing the temporal-spectral structure of quantum states of light, and photonic quantum computation.
Optical chips for quantum photonics are cutting-edge technology, merging photonics and quantum mechanics to manipulate light at the quantum level. These chips are crucial for advancing quantum computing, secure communication, and precision sensing by integrating photonic components such as waveguides, beam splitters, and detectors to manipulate single photons, the fundamental carriers of quantum information. Key advancements in optical chips include low-loss waveguides, efficient single-photon sources, and high-fidelity quantum gates, all essential for scalable quantum circuits. Integrating these circuits on a chip offers significant advantages in miniaturization, stability, and reproducibility over traditional bulk optics setups. Recent breakthroughs in materials science and nanofabrication have propelled the field forward, enabling the production of chips with higher precision and lower defect rates. Silicon photonics, in particular, has become a prominent platform due to its compatibility with existing semiconductor manufacturing processes, facilitating the integration of quantum photonic circuits with classical electronic systems. Here, we share our vision of the future of optical chips for quantum photonics, which hold promise for various applications. In quantum computing, they enable the development of compact and scalable quantum processors. In communication, they provide the foundation for ultra-secure quantum networks through quantum key distribution. In sensing, they allow for high-precision measurements that surpass classical limits. As research progresses, optical chips are expected to play a critical role in realizing the full potential of quantum technologies.
In recent years, the field of quantum nanophotonics has been thriving with an intense interest in the development of new theories, devices, and applications for specific uses.This special issue on "Quantum nanophotonics" highlights some recent developments in this topic through reviews, perspectives, and research papers.This issue contains review and perspective articles that provide a comprehensive overview of cutting-edge topics.Chang and Zwiller [1] review the recent progresses in integrated quantum photonics using nanowires, focusing on integrated emitters, detectors, and fabrication methods.This review also presents the applications for quantum information processing and sensing based on nanowires.Gali [2] summarizes the ab initio theory to fully understand solid-state qubits, which are an essential component in the quantum photonic device.This computational method has been applied to the calculation of excited states, photo-ionization threshold, optical excitation spectra, effective mass states, and spin dynamics.This approach could give insights beyond conventional density functional theory that cannot fully capture the characteristics of excited states.Biotechnologies are being used in a variety of quantum optics and photonics or vice versa.DNA nanotechnology, using the information of DNA to design and manufacture artificial nucleic acid structures for technological uses, has been utilized in the field of quantum emitters.Exotic traits of DNA enable the grabbing of quantum emitters and steering of their directors at the molecular level of resolution.The relevant studies were extensively reviewed by Cho et al. [3].Reversely, the understanding of light-matter interaction in quantum optics provides a hint to investigate chemical and biological processes.Kim et al. [4] present a review of plexcitonic and vibro-polaritonic strong coupling based on light-matter interaction with optical resonators.The authors introduce from fundamentals of strong coupling, configuration and characteristics of plexcitons, and applications for chemistry and biological detection.Kim et al. [5] discuss that nanophotonic resonance engineering can make the near-unity readout fidelity necessary for improving the sensitivity of NV quantum sensing.The perspective gives insight into the background of NV quantum sensing, applications of resonant structures, and the remaining challenges for practical sensing.Zheng and Kim [6] address the degradation mechanisms of perovskite-based light-emitting diodes.The degradation can potentially occur in external and internal processes, leading to distinct effects on performance and stability.Various research articles on quantum nanophotonics are included.There is growing interest in optimizing the single photon emitter (SPE) that can be integrated into the photonic circuit and enable practical application.Azzam et al. [7] demonstrate the Purcell enhancement of WSe 2 SPE using a dielectric cavity.The dielectric cavity imposes an oriented strain profile on the WSe 2 , which can make the polarization state of the SPE selectively controlled.Xu et al. [8] report a high-purity SPE based on nanodiamonds (NDs) with negatively charged silicon vacancy (SiV -) centers using an ion implantation method.They successfully prevent SiV -emitters from