On-chip spectropolarimetry by fingerprinting with random surface arrays of nanoparticles

Optical metasurfaces revolutionized the approach to moulding the propagation of light by enabling simultaneous control of the light phase, momentum, amplitude and polarization. Thus, instantaneous spectropolarimetry became possible by conducting parallel intensity measurements of differently diffracted optical beams. Various implementations of this very important functionality have one feature in common - the determination of wavelength utilizes dispersion of the diffraction angle, requiring tracking the diffracted beams in space. Realization of on-chip spectropolarimetry calls thereby for conceptually different approaches. In this work, we demonstrate that random nanoparticle arrays on metal surfaces, enabling strong multiple scattering of surface plasmon polaritons (SPPs), produce upon illumination complicated SPP scattered patterns, whose angular spectra are uniquely determined by the polarization and wavelength of light, representing thereby spectropolarimetric fingerprints. Using um-sized circular arrays of randomly distributed {\mu}m-sized gold nanoparticles (density ~ 75 {\mu}m$^-$$^2$}) fabricated on gold films, we measure angular distributions of scattered SPP waves using the leakage radiation microscopy and find that the angular SPP spectra obtained for normally incident light beams different in wavelength and/or polarization are distinctly different. Our approach allows one to realize on-chip spectropolarimetry by fingerprinting using surface nanostructures fabricated with simple one-step electron-beam lithography.Comment: 22 pages, 5 figure

Single-qubit optical quantum fingerprinting

We analyze and demonstrate the feasibility and superiority of linear optical single-qubit fingerprinting over its classical counterpart. For one-qubit fingerprinting of two-bit messages, we prepare `tetrahedral' qubit states experimentally and show that they meet the requirements for quantum fingerprinting to exceed the classical capability. We prove that shared entanglement permits 100% reliable quantum fingerprinting, which will outperform classical fingerprinting even with arbitrary amounts of shared randomness.Comment: 4 pages, one figur

Performing the Union: the Prüm Decision and the European dream

In 2005, seven European countries signed the so-called Prüm Treaty to increase transnational collaboration in combating international crime, terrorism and illegal immigration. Three years later, the Treaty was adopted into EU law. EU member countries are obliged to have systems in place to allow authorities of other member states access to nationally held data on DNA, fingerprints, and vehicles by August 2011. In this paper, we discuss the conditions of possibility for the Prüm network to emerge, and argue that rather than a linear story of technological and political convergence and harmonisation, the (hi)story of Prüm is heterogeneous and patchy. This is reflected also in the early stages of implementing the Prüm Decision which proves to be more difficult than it was hoped by the drivers of the Prüm process. In this sense, the Prüm network sits uncomfortably with success stories of forensic science (many of which served the goal of justifying the expansion of technological and surveillance systems). Instead of telling a story of heroic science, the story of Prüm articulates the European dream: One in which goods, services, and people live and travel freely and securely

LocNet: Global localization in 3D point clouds for mobile vehicles

Global localization in 3D point clouds is a challenging problem of estimating the pose of vehicles without any prior knowledge. In this paper, a solution to this problem is presented by achieving place recognition and metric pose estimation in the global prior map. Specifically, we present a semi-handcrafted representation learning method for LiDAR point clouds using siamese LocNets, which states the place recognition problem to a similarity modeling problem. With the final learned representations by LocNet, a global localization framework with range-only observations is proposed. To demonstrate the performance and effectiveness of our global localization system, KITTI dataset is employed for comparison with other algorithms, and also on our long-time multi-session datasets for evaluation. The result shows that our system can achieve high accuracy.Comment: 6 pages, IV 2018 accepte