Near-IR wide field-of-view Huygens metalens for outdoor imaging applications

The ongoing effort to implement compact and cheap optical systems is the main driving force for the recent flourishing research in the field of optical metalenses. Metalenses are a type of metasurface, used for focusing and imaging applications, and are implemented based on the nanopatterning of an optical surface. The challenge faced by metalens research is to reach high levels of performance, using simple fabrication methods suitable for mass-production. In this paper we present a Huygens nanoantenna based metalens, designed for outdoor photographic/surveillance applications in the near-infra-red. We show that good imaging quality can be obtained over a field-of-view (FOV) as large as +/-15 degrees. This first successful implementation of metalenses for outdoor imaging applications is expected to provide insight and inspiration for future metalens imaging applications

How good is your metalens? Experimental verification of metalens performance criterion

A metric for evaluation of overall metalens performance is presented. It is applied to determination of optimal operating spectral range of a metalens, both theoretically and experimentally. This metric is quite general and can be applied to the design and evaluation of future metalenses, particularly achromatic metalenses

SPICE: Simulation Package for Including Flavor in Collider Events

We describe SPICE: Simulation Package for Including Flavor in Collider Events. SPICE takes as input two ingredients: a standard flavor-conserving supersymmetric spectrum and a set of flavor-violating slepton mass parameters, both of which are specified at some high "mediation" scale. SPICE then combines these two ingredients to form a flavor-violating model, determines the resulting low-energy spectrum and branching ratios, and outputs HERWIG and SUSY LesHouches files, which may be used to generate collider events. The flavor-conserving model may be any of the standard supersymmetric models, including minimal supergravity, minimal gauge-mediated supersymmetry breaking, and anomaly-mediated supersymmetry breaking supplemented by a universal scalar mass. The flavor-violating contributions may be specified in a number of ways, from specifying charges of fields under horizontal symmetries to completely specifying all flavor-violating parameters. SPICE is fully documented and publicly available, and is intended to be a user-friendly aid in the study of flavor at the Large Hadron Collider and other future colliders.Comment: 31 pages, 3 figures, SPICE can be downloaded from http://hep.ps.uci.edu/~spice; v2: published versio

Anti-Stokes Photoluminescence in Monolayer WSe2_2 Activated by Plasmonic Cavities through Resonant Excitation of Dark Excitons

Anti-Stokes photoluminescence (PL) is light emission at a higher photon energy than the excitation, with applications in optical cooling, bioimaging, lasing, and quantum optics. Here, we show how plasmonic nano-cavities activate anti-Stokes PL in WSe$_2$ monolayers through resonant excitation of a dark exciton. The tightly confined plasmonic fields excite the out-of-plane transition dipole of the dark exciton, leading to light emission from the bright exciton at higher energy. Through statistical measurements on hundreds of plasmonic cavities, we show that coupling to the dark exciton is key to achieving a near hundred-fold enhancement of the upconverted PL intensity. This is further corroborated by experiments in which the laser excitation wavelength is tuned across the dark exciton. Finally, we show that an asymmetric nanoparticle shape and precise geometry are key for consistent activation of the dark exciton and efficient PL upconversion. Our work introduces a new excitation channel for anti-Stokes PL in WSe$_2$ and paves the way for large-area substrates providing optical cooling, anti-Stokes lasing, and radiative engineering of excitons

Integrating Approaches to Privacy Across the Research Lifecycle: When Is Information Purely Public?

On September 24-25, 2013, the Privacy Tools for Sharing Research Data project at Harvard University held a workshop titled "Integrating Approaches to Privacy across the Research Data Lifecycle." Over forty leading experts in computer science, statistics, law, policy, and social science research convened to discuss the state of the art in data privacy research. The resulting conversations centered on the emerging tools and approaches from the participants’ various disciplines and how they should be integrated in the context of real-world use cases that involve the management of confidential research data. Researchers are increasingly obtaining data from social networking websites, publicly-placed sensors, government records and other public sources. Much of this information appears public, at least to first impressions, and it is capable of being used in research for a wide variety of purposes with seemingly minimal legal restrictions. The insights about human behaviors we may gain from research that uses this data are promising. However, members of the research community are questioning the ethics of these practices, and at the heart of the matter are some difficult questions about the boundaries between public and private information. This workshop report, the second in a series, identifies selected questions and explores issues around the meaning of “public” in the context of using data about individuals for research purposes

The new paradigm and mental models

In a recent article in this journal, Johnson–Laird and colleagues argue that mental models theory (MMT) can integrate logical and probabilistic reasoning [1]. We argue that Johnson-Laird and colleagues make a radical revision of MMT, but to ill effect. This can best be seen in what they say about truth and validity (Box 1). Formerly ([2], p. 651), in MMT p ∨ q (p or q) ‘... is true provided that at least one of its two disjuncts is true; otherwise, it is false.’ Thus p ∨ q is true provided that one of three possibilities is true: p & not-q, not-p & q, p & q. However, Johnson-Laird et al. claim, ‘The disjunction is true provided that each of these three cases [p & not-q, not-p & q, p & q] is possible.’ However, these three cases are always possible for jointly contingent statements: that is why they are rows of the truth table for p ∨ q. This new definition makes almost every disjunction true. An example of a disjunction that it does not make true is p ∨ not-p. This tautology fails to be true for their account because p & not-p is not possible