Kvantfotonik

Kvantfotonik, or quantum photonics, is the study and application of quantum properties of light for information processing, communication, sensing and metrology. It focuses on manipulating and measuring quantum states of photons, such as superposition and entanglement, to enable tasks beyond classical capabilities.

Key concepts include photons as carriers of quantum information (qubits), nonclassical light states (single photons, entangled pairs, squeezed states) and the use of quantum interference. Essential technologies encompass sources of high-purity single photons and entangled photons (quantum dots, color centers, heralded photons), highly efficient detectors (superconducting nanowire single-photon detectors and other SPADs), and integrated photonics that route light on chips.

Technologies developed in kvantfotonik often involve silicon nitride, silicon, or lithium niobate platforms for photonic integration, enabling scalable networks of waveguides, beamsplitters and modulators. Related components include quantum memories for temporary storage of photonic states and frequency converters to bridge different wavelength regimes, supporting quantum networks and interfacing with existing communication infrastructure.

Applications span quantum communication, notably quantum key distribution and secure networks; photonic quantum computing and simulators based on linear optics and measurement-based models; and quantum-enhanced sensing and metrology, where quantum correlations improve precision in imaging, spectroscopy and interferometry.

The field is interdisciplinary, bringing together physics, electrical engineering, materials science and computer science. Research programs typically aim to improve photon sources and detectors, reduce losses, advance large-scale photonic integration, and develop robust quantum networks and practical devices. Challenges include scalability, integration with classical systems, and ensuring reliability and cost-effectiveness for real-world deployment.