Simulation of high-Q nanocavities with 1D photonic gap

We report on theoretical investigation of a hybrid cavity structure which has been conducted within the European Action COST MP0702. The structure, which can reach ultrahigh Q factors, consists of a size-modulated 1D stack cavity made in a III-V material and coupled to a silicon waveguide. We present results of structure behavior simulations obtained by four independent rigorous numerical techniques. We discuss qualitative physical properties of the simulations results and identify the main physical effects contributing to the total Q factor

Present and Future of SLAM in Extreme Underground Environments

This paper reports on the state of the art in underground SLAM by discussing different SLAM strategies and results across six teams that participated in the three-year-long SubT competition. In particular, the paper has four main goals. First, we review the algorithms, architectures, and systems adopted by the teams; particular emphasis is put on lidar-centric SLAM solutions (the go-to approach for virtually all teams in the competition), heterogeneous multi-robot operation (including both aerial and ground robots), and real-world underground operation (from the presence of obscurants to the need to handle tight computational constraints). We do not shy away from discussing the dirty details behind the different SubT SLAM systems, which are often omitted from technical papers. Second, we discuss the maturity of the field by highlighting what is possible with the current SLAM systems and what we believe is within reach with some good systems engineering. Third, we outline what we believe are fundamental open problems, that are likely to require further research to break through. Finally, we provide a list of open-source SLAM implementations and datasets that have been produced during the SubT challenge and related efforts, and constitute a useful resource for researchers and practitioners.Comment: 21 pages including references. This survey paper is submitted to IEEE Transactions on Robotics for pre-approva

Coupling of waveguide mode and graphene plasmons

Photonic waveguides with graphene layers have been recently studied for their potential as fast and low-power electro-optic modulators with small footprints. We show that in the optical wavelength range of 1.55 μm, surface plasmons supported by the graphene layer with the chemical potential exceeding ~0.5 eV can couple with the waveguide mode and affect its propagation. This effect might be possibly utilized in technical applications as a very low-power amplitude modulation, temperature sensing, etc

Safe Documentation of Historical Monuments by an Autonomous Unmanned Aerial Vehicle

The use of robotic systems, especially multi-rotor aerial vehicles, in the documentation of historical buildings and cultural heritage monuments has become common in recent years. However, the teleoperated robotic systems have significant limitations encouraging the ongoing development of autonomous unmanned aerial vehicles (UAVs). The autonomous robotic platforms provide a more accurate and safe measurement in distant and difficult to access areas than their teleoperated counterpart. Through the use of autonomous aerial robotic systems, access to such places by humans and building of external infrastructures like scaffolding for documentation purposes is no longer necessary. In this work, we aim to present a novel autonomous unmanned aerial vehicle designed for the documentation of hardly attainable areas of historical buildings. The prototype of this robot was tested in several historical monuments comprising scanned objects located in dark and hardly accessible areas in the upper parts of tall naves. This manuscript presents the results from two specific places: the Church of St. Anne and St. Jacob the Great in Stará Voda, and St. Maurice Church in Olomouc, both in the Czech Republic. Finally, we also compare the three-dimensional map obtained with the measurements made by the 3D laser scanner carried onboard UAV against the ones performed by a 3D terrestrial laser scanner

Methodics of using UAV technology for documentation of interiors & exteriors of historical monuments

Methodics deals with process of documentation of exteriors of historical objects by UAV, including adequate legislative. But the main issue is documentation of interiors of arthistorical value by drones - through our unique safe documentation method. Methods accompanies case studies, included are general informations about drones and digitalization of historical mouments