The COST Action MP1403 “Nanoscale Quantum Optics” (NQO) has recently released a NQO Roadmap identifying research priorities that address both classical and quantum schemes in information and communication technology, sensing and metrology, and energy efficiency. Based on the Roadmap, the COST Action has been working on a Market Research Study (MRS) to assess the potential of NQO for selected applications and markets in a more quantitative manner. The MRS has been carried out with the cooperation of Tematys and it has been focused on two areas: (i) quantum sensing, imaging and measurement systems: achieve unprecedented sensitivity, accuracy and resolution in measurement and imaging by coherently manipulating quantum objects and (ii) quantum communications: guarantee secure data transmission and long-term security for the information society by using quantum resources for communication protocols. The MRS has primarily addressed near-term technologies, like quantum random number generators (QRNG) for secure key or token generation and point-to-point quantum key distribution (QKD) for secure key exchange in crypto systems. Mid/long-term technologies like QKD networks, quantum memories and repeaters have not been assessed. Likewise for quantum sensing, imaging and metrology the focus has been on near-term technologies like magnetic resonance imaging (MRI), magnetic/electric field detection for materials analysis and biosensing, precision metrology and gravimetric sensors for civil and defense applications. The MRS has also taken into account quantum enabling technologies, which are fundamental components for the construction of quantum-photonics systems.
The COST Action MP1403 “Nanoscale Quantum Optics” (NQO) has recently released a NQO Roadmap identifying research priorities that address both classical and quantum schemes in information and communication technology, sensing and metrology, and energy efficiency. Based on the Roadmap, the COST Action has been working on a Market Research Study (MRS) to assess the potential of NQO for selected applications and markets in a more quantitative manner. The MRS has been carried out with the cooperation of Tematys and it has been focused on two areas: (i) quantum sensing, imaging and measurement systems: achieve unprecedented sensitivity, accuracy and resolution in measurement and imaging by coherently manipulating quantum objects and (ii) quantum communications: guarantee secure data transmission and long-term security for the information society by using quantum resources for communication protocols. The MRS has primarily addressed near-term technologies, like quantum random number generators (QRNG) for secure key or token generation and point-to-point quantum key distribution (QKD) for secure key exchange in crypto systems. Mid/long-term technologies like QKD networks, quantum memories and repeaters have not been assessed. Likewise for quantum sensing, imaging and metrology the focus has been on near-term technologies like magnetic resonance imaging (MRI), magnetic/electric field detection for materials analysis and biosensing, precision metrology and gravimetric sensors for civil and defense applications. The MRS has also taken into account quantum enabling technologies, which are fundamental components for the construction of quantum-photonics systems.
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.
Nanoscale quantum optics explores quantum phenomena in nanophotonics systems for advancing fundamental knowledge in nano and quantum optics and for harnessing the laws of quantum physics in the development of new photonics-based technologies. Here, we review recent progress in the field with emphasis on four main research areas: Generation, detection, manipulation and storage of quantum states of light at the nanoscale, Nonlinearities and ultrafast processes in nanostructured media, Nanoscale quantum coherence, Cooperative effects, correlations and many-body physics tailored by strongly confined optical fields. The focus is both on basic developments and technological implications, especially for what concerns information and communication technology, sensing and metrology, and energy efficiency.
Background: High-precision sensing is vital for modern technology, yet conventional sensors are fundamentally constrained by classical noise limits. Quantum sensing leverages principles of quantum mechanics, such as superposition and entanglement, to overcome these barriers, offering unprecedented sensitivity. This review comprehensively analyzes the current state of quantum sensor technology, focusing on its underlying physical principles, emerging applications, and the pathway toward industrial maturation.Methods: We synthesize findings from key research areas, detailing the foundational quantum systems like Nitrogen-Vacancy (NV) centers in diamond and advanced optical techniques. The paper reviews the theoretical methods used to achieve sub-shot-noise performance and discusses the system-level engineering challenges necessary for practical deployment, particularly concerning microwave control and optical readout. We also assess the current landscape of standardization efforts for quantum technologies.Results: Significant breakthroughs are highlighted in both biomedical and environmental sensing. Applications range from tracking cellular redox-status using electron-paramagnetic resonance to ultra-sensitive salinity measurements. The analysis confirms that quantum sensing provides superior resolution compared to classical counterparts, unlocking new capabilities in in-vivo and real-time monitoring.Discussion: While offering transformative potential, widespread adoption faces hurdles, including the maintenance of quantum coherence in ambient environments and the high cost and complexity of current instrumentation. Future efforts must focus on miniaturization, integration with classical systems, and standardized fabrication protocols. Quantum sensing represents the next-generation technological paradigm for metrology.
Quantum communication and information technologies are poised to transform secure data transmission, distributed quantum computing, and scalable networking by leveraging fundamental principles such as superposition, entanglement, and the no-cloning theorem. This survey presents a structured overview of the quantum information processing (QIP) landscape, spanning theoretical foundations to system-level architectures. We cover quantum states, unitary evolution, gates, and channels, leading to the mathematical framework of quantum operations and the effects of decoherence. Quantum error correction (QEC) is examined through block codes and fault-tolerant operations, along with its integration with entanglement purification to address challenges of noisy intermediate-scale quantum (NISQ) devices. Physical platforms, including gate-based, continuousvariable and measurement-based models, are analyzed with an emphasis on error mitigation strategies to preserve coherence. We also discuss advancements in quantum sensing, particularly phase estimation, and evaluate communication protocols such as quantum key distribution (QKD) and teleportation in terms of fidelity, efficiency, and resilience. At the system level, components such as quantum networks, repeaters, and routers are reviewed with attention to scalability and security. Each section concludes with lessons learned, reflecting on challenges, trade-offs, and open questions. The survey culminates in outlining future directions in hybrid QEC-sensing integration, AI-enhanced error correction, and topological architectures, offering a forward-looking perspective on the co-evolution of quantum technologies. By bridging theory, protocols, physical systems, and architectures, this work charts a comprehensive roadmap toward secure, scalable, and high-fidelity quantum communication.
Quantum technologies have emerged as critical enablers of next-generation communication, computation, and sensing systems. This review aims to assess the current state of Quantum Key Distribution (QKD) and related quantum technologies by examining recent empirical findings, methodological innovations, and systemic challenges. A structured literature search was conducted across Scopus, PubMed, and Google Scholar using Boolean keyword combinations targeting QKD, quantum sensing, and communication applications. The review focused on peer-reviewed articles from the last five years and included experimental studies, simulations, and applied case analyses. Findings show that QKD has demonstrated remarkable reliability in both controlled laboratory and real-world settings. Studies on multicore fiber networks highlight the potential for high-dimensional communication security, while comparative analyses reveal disparities between implementation strategies across different regions. However, systemic challenges such as inadequate infrastructure, inconsistent regulation, and insufficient public understanding hinder wide-scale adoption. The discussion identifies critical factors contributing to these challenges and proposes actionable policy recommendations, including increased investment in infrastructure, standardized regulations, and targeted education programs. This review concludes that achieving the full potential of quantum technologies will require integrative strategies addressing technical, institutional, and social dimensions. Future research should emphasize longitudinal evaluation and interdisciplinary collaboration to enhance scalability and impact. The insights offered here provide a foundational framework for policymakers, researchers, and industry leaders to advance the adoption of secure, scalable quantum systems.
Quantum metrology provides a route to overcome practical limits in sensing devices. It holds particular relevance to biology, where sensitivity and resolution constraints restrict applications both in fundamental biophysics and in medicine. Here, we review quantum metrology from this biological context, focusing on optical techniques due to their particular relevance for biological imaging, sensing, and stimulation. Our understanding of quantum mechanics has already enabled important applications in biology, including positron emission tomography (PET) with entangled photons, magnetic resonance imaging (MRI) using nuclear magnetic resonance, and bio-magnetic imaging with superconducting quantum interference devices (SQUIDs). In quantum metrology an even greater range of applications arise from the ability to not just understand, but to engineer, coherence and correlations at the quantum level. In the past few years, quite dramatic progress has been seen in applying these ideas into biological systems. Capabilities that have been demonstrated include enhanced sensitivity and resolution, immunity to imaging artifacts and technical noise, and characterization of the biological response to light at the single-photon level. New quantum measurement techniques offer even greater promise, raising the prospect for improved multi-photon microscopy and magnetic imaging, among many other possible applications. Realization of this potential will require cross-disciplinary input from researchers in both biology and quantum physics. In this review we seek to communicate the developments of quantum metrology in a way that is accessible to biologists and biophysicists, while providing sufficient detail to allow the interested reader to obtain a solid understanding of the field. We further seek to introduce quantum physicists to some of the central challenges of optical measurements in biological science.