In this review, the progress on the research development in electromagnetic wave propagation through temporal/time-varying media is presented. Such media refers to materials or environments whose properties change over time. Therefore, unlike spatial waveguides that manipulate light based on spatial configuration of the structure, the temporal waveguides focus on the evolution of light pulses over time. Understanding temporal media is essential for developing advanced communication protocols, efficient waveguides, and accurate simulations of physical systems, ultimately improving the design and performance of various applications in science and technology. As the controlled light matter interactions in the time domain offers numerous advanced applications for secured optical communication, information processing and ultrafast optics in the realm of quantum technology. The recent advances in light-matter interactions in temporal media have openedexciting avenues for manipulating light at unprecedented levels, leading to novel applications in fields like quantum computing, telecommunications, and material science.
In this review, the progress on the research development in electromagnetic wave propagation through temporal/time-varying media is presented. Such media refers to materials or environments whose properties change over time. Therefore, unlike spatial waveguides that manipulate light based on spatial configuration of the structure, the temporal waveguides focus on the evolution of light pulses over time. Understanding temporal media is essential for developing advanced communication protocols, efficient waveguides, and accurate simulations of physical systems, ultimately improving the design and performance of various applications in science and technology. As the controlled light matter interactions in the time domain offers numerous advanced applications for secured optical communication, information processing and ultrafast optics in the realm of quantum technology. The recent advances in light-matter interactions in temporal media have openedexciting avenues for manipulating light at unprecedented levels, leading to novel applications in fields like quantum computing, telecommunications, and material science.
Intense light-matter interaction largely relies on the use of high-power light sources, creating fields comparable to, or even stronger than, the field keeping the electrons bound in atoms. Under such conditions, the interaction induces highly nonlinear processes such as high harmonic generation, in which the low-frequency photons of a driving laser field are upconverted into higher-frequency photons. These processes have enabled numerous groundbreaking advances in atomic, molecular, and optical physics, and they form the foundation of attosecond science. Until recently, however, such processes were typically described using semi-classical approximations, since the quantum properties of the light field were not required to explain the observables. This has changed in the recent past. Ongoing theoretical and experimental advances show that fully quantized descriptions of intense light-matter interactions, which explicitly incorporate the quantum nature of the light field, open new avenues for both fundamental research and technological applications at the fully quantized level. These advances emerge from the convergence of quantum optics with strong-field physics and ultrafast science. Together, they have given rise to the field of quantum optics and quantum electrodynamics of strong-field processes.
The interaction of light and matter at the single-photon level is of central importance in various fields of physics, including, e.g., condensed matter physics, astronomy, quantum optics, and quantum information. Amplification of such quantum light–matter interaction can be highly beneficial to, e.g., improve device performance, explore novel phenomena, and understand fundamental physics, and has therefore been a long-standing goal. Furthermore, simulation of light–matter interaction in the regime of ultrastrong coupling, where the interaction strength is comparable to the bare frequencies of the uncoupled systems, has also become a hot research topic, and considerable progress has been made both theoretically and experimentally in the past decade. In this review, we provide a detailed introduction of recent advances in amplification of quantum light–matter interaction and simulation of ultrastrong light–matter interaction, particularly in cavity and circuit quantum electrodynamics and in cavity optomechanics.
Recent progress in meta-optics, particularly the development of metasurfaces, has enabled compact, tunable, and integrable control over the amplitude, phase, polarization, and wavefront of light, thereby allowing a paradigm shift in traditional optical science and engineering. In parallel, the ability to generate and precisely manipulate nonclassical light is central to quantum optics, enabling key functionalities in secure quantum communication, precision measurement, and scalable quantum computation. This review aims to bridge these two rapidly advancing fields by presenting recent progress in the application of structured materials to the manipulation of quantum states of light. We begin by introducing the concept of singular optics, followed by a discussion of various families of spatially and temporally structured beams that form the foundation for many of the phenomena explored in quantum photonics. Next, we revisit the theoretical framework of quantum optics, including the formalism of photon quantization and the principles governing quantum frequency conversion. We then examine how metasurfaces can be engineered to enable highly efficient nonlinear quantum processes, including both up-conversion and down-conversion, thereby offering new approaches for generating and controlling complex quantum states. Furthermore, we discuss the crucial role of structured materials in shaping the properties of quantum light and in applications such as quantum ghost imaging. The review concludes by identifying emerging directions for integrating meta-optical platforms with quantum systems, highlighting their potential for scalable manipulation of nonclassical light at the nanoscale.
The quantum level interaction between light and mechanical systems has become a cutting-edge research with broad implications for fundamental physics, quantum information processing, and sensing. Quantum optomechanical systems allow for the precise control and modulation of light-matter interactions by coupling photons with mechanical resonators. Novel approaches to the manipulation of light and matter quantum states have been made possible by recent developments in the fabrication of ultra-sensitive mechanical devices and the achievement of strong coupling regimes. the most recent advancements in quantum optomechanics, such as the realization of non-classical states of light and mechanical motion, the improvement of quantum coherence, and the cooling of mechanical systems to their quantum ground state. possible uses in quantum memory, extremely accurate measurement systems, and basic quantum mechanical experiments. In order to create more reliable and scalable quantum networks, the study concludes by outlining potential future avenues for combining quantum optomechanical systems with other quantum technologies.
The field of high-dimensional quantum photonics involves the use of multimode photonic degrees-of-freedom such as the spatial, temporal, or spectral structure of light to encode multi-level quantum states. Recent years have seen rapid progress in the development of methods to generate, manipulate, and distribute such quantum states of light and their use in a range of quantum technology applications that offer practical advantages over conventional qubit-based approaches. High-dimensional quantum states of light encoded in photonic time-bins, frequency-bins, transverse-spatial modes, waveguide paths, and temporal modes have enabled noise-robust fundamental tests of quantum mechanics, error-resilient and high-capacity quantum communication protocols, andas well as efficient approaches for quantum information processing, to name just a few examples. However, research in this field has progressed fairly independently, with little exchange across different photonic degrees-of-freedom or between experiment and theory and no comprehensive comparison between degrees-of-freedom. This roadmap aims to bridge this gap by surveying progress in each area and identifying shared challenges and opportunities that cut across two or more photonic degrees-of-freedoms. We review early work and state-of-the-art experimental techniques under development for high-dimensional quantum states encoded in single and entangled photons, as well as theoretical tools for their measurement and certification. We outline the main outstanding challenges for theory and each experimental degree-of-freedom, identifying promising future directions of research that may enable these to be overcome. We end by discussing interconnections and shared challenges centered around their distribution, measurement, and manipulation, with a view towards their integration into next-generation quantum technology platforms and applications.
Quantum optics, the study of light and its interactions with matter at the quantum level, has revolutionized modern telecommunications. By leveraging quantum phenomena such as entanglement, superposition, and photon manipulation, quantum optics enables ultra-secure communication, high-speed data transfer, and novel computing paradigms. The integration of quantum technologies into emerging communication infrastructures, particularly 6G networks, is becoming increasingly critical for overcoming the inherent limitations of classical communication and computation. In summary, quantum optics and quantum information have profoundly influenced modern physics and technology, where the field continues to bridge fundamental research and practical applications, promising further innovations in the future. The exponential growth of data traffic necessitates advancements in secure and high-speed communication technologies. Classical telecommunications rely on electromagnetic waves, but quantum optics introduces fundamentally new capabilities by exploiting quantum states of light. This paper explores the fundamental principles of quantum optics, its applications in quantum key distribution (QKD), quantum teleportation, and quantum repeaters, and its impact on next-generation telecommunications. We also discussed challenges and future prospects of the quantum optics in telecommunications.