Photons, the individual quanta of the light field, are what the science of quantum photonics is dedicatedly investigating. The manipulation and coherent control of photons in quantum photonics enables the exploration of various quantum phenomena of high fundamental interest. In the meantime, due to the fast speed and a lack of the interaction with the environment, photons are now regarded as a promising platform for the emerging quantum information processing (QIP) studies. Therefore, there is a growing number of works on quantum computing, quantum communication, and quantum metrology that are solidly based on the techniques of quantum photonics.
Photons, the individual quanta of the light field, are what the science of quantum photonics is dedicatedly investigating. The manipulation and coherent control of photons in quantum photonics enables the exploration of various quantum phenomena of high fundamental interest. In the meantime, due to the fast speed and a lack of the interaction with the environment, photons are now regarded as a promising platform for the emerging quantum information processing (QIP) studies. Therefore, there is a growing number of works on quantum computing, quantum communication, and quantum metrology that are solidly based on the techniques of quantum photonics.
Single photons and individual quantum systems are at the heart of recent developments in quantum technologies and are about to enable a variety of novel applications in sensing, communication, and computing. Photonic devices are the key to control interactions between quantum systems and light as well as to simultaneously engineer the properties of photons. For scalable quantum technologies, the employed quantum systems are solid-state based, thus placing the field of quantum photonics at the intersection of physics, nanotechnology, and material sciences. This special issue features 14 contributions and addresses recent advances in several material platforms.
Quantum information science has emerged to consider what additional power and functionality can be realized in the encoding, transmission, and processing of information by specifically harnessing quantum mechanical effects. Anticipated technologies include quantum key distribution, which offers perfectly secure communication; quantum metrology, which allows more precise measurements than could ever be achieved without quantum mechanics; and quantum lithography, which could enable fabrication of devices with features much smaller than the wavelength of light. Perhaps the most profound future technology is a quantum computer that promises exponentially faster operation for particular tasks. Of the various physical systems being pursued, an all-optical quantum computer, which encodes quantum information in single photons, has emerged as a leading approach. Here we give a brief review of this field, focusing on some of our recent work.
Modern quantum nanophotonics is revealed as the unique synergy between the quantum world and nanophotonics providing us with novel ways of controlling the quantum states of light, and enabling novel routes towards the realisation of future generation’s quantum information processing (QIP) systems. Focusing on the quantum photon-matter interaction, nano-confined light, nano-optical quantum interference and the control of linear and nonlinear quantum phenomena at the nanoscale in terms of the quantum superposition and entanglement, we provide a fundamental description of nano-photonic quantum systems. In particular, deep discussions on the outstanding characteristics of nano-structured photonic circuits are essential to understand the strong light-matter coupling, capable of boosting the coherence times and the processing efficiency of qubits, i.e., the basic building blocks of quantum computing. Furthermore, a progressive approach dealing with the QIP functionalities within concepts of quantum communication networks and powerful quantum computational architectures is provided, motivating an empirical hunt for efficient QIP approaches. Positive perspectives are given on the potential implications of modern quantum nanophotonics to the theoretical frameworks of the field.
In this talk I shall present a brief overview on some recent exciting experimental progress towards scalable quantum information processing (QIP), e.g., quantum communication, quantum computation and quantum simulation, via manipulation of photonic qubits. Building on our long experience in research on multi-photon entanglement, we are working on a number of experiments in the field of QIP with particular emphasis on linear optical quantum computation and free space quantum communication. It is foreseen that with ongoing development, quantum communication over 1000 km scale and coherent quantum manipulation of up to a few tens photonic qubits shall be feasible in the next five years.
Quantum optics is the branch of physics that investigates the interaction of light with matter at the quantum level, where the discrete nature of photons and quantum states of atoms, molecules, and solid-state systems become dominant. Quantum optics systems provide the experimental and theoretical foundation for understanding nonclassical states of light, quantum coherence, entanglement, and measurement at the quantum limit. Over the past few decades, advances in laser technology, nonlinear optics, and precision measurement have transformed quantum optics from a fundamental discipline into a key enabler of quantum technologies, including quantum communication, quantum computing, quantum sensing, and quantum metrology. This review presents a comprehensive overview of the physical principles, system architectures, and experimental platforms of quantum optics. Emphasis is placed on light sources, atom–photon interaction systems, detection techniques, and emerging applications, along with current challenges and future research directions.
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.