Quantum cryptography with structured photons

Abstract

Quantum photonic platforms have proven to be essential in realizing fundamentally secure quantum transfer of information, with commercially ready systems already deployed in municipal and terrestrial links. The drive toward higher bit rates and robustness to eavesdropping and noisy channels has focused attention on moving from the present two-dimensional quantum states of polarization, to harnessing all of light's degrees of freedom for multi-dimensional quantum coding with structured photons. In this Perspective, we outline the present state-of-the-art in achieving this control with spatial modes of light, both as single photon and entangled states, highlight the open challenges that remain, and consider the roadmap that might see its full potential realized.

Synergy between AI and Optical Metasurfaces: A Critical Overview of Recent Advances

“…It is a short cross-section of the state of the art presented for illustrative purposes only, i.e., without systematization, while the real number of applications, patents and research teams is hard even to guess since it increases on a daily basis. As far as the more advanced applications are concerned, some of them include optofluidic devices [100] for microreactors encompassing photocatalysis [101], lab-on-chip technologies [102]; optical tweezers for micro-and nanoparticle trapping and manipulation [103]; optical levers for atomic force microscopy [104]; biomedical imaging [105], e.g., optical coherence tomography [106], terahertz imaging [107]; super-resolution microscopy beyond the Abbe diffraction limit [108] including the use of superlenses and hyperlenses [109]; nonlinear optical devices for frequency conversion [110]; quantum optics [33] for quantum computing [111] and quantum cryptography [112]; stealth coatings [113]; optical cloaking devices (invisibility shields) [114,115], nonreciprocal cloaking (cloak that hides objects from the outside viewpoint but permits looking from the object outward) [116]; camouflage into virtual objects (electromagnetic illusions) [117,118]; and general transformation optics [119] (including its applications in, e.g., astrophysical all-optical simulation and the related models in other fields [120]).…”