Observation of trapped light within the radiation continuum

The ability to confine light is important both scientifically and technologically. Many light confinement methods exist, but they all achieve confinement with materials or systems that forbid outgoing waves. These systems can be implemented by metallic mirrors, by photonic band-gap materials, by highly disordered media (Anderson localization) and, for a subset of outgoing waves, by translational symmetry (total internal reflection) or by rotational or reflection symmetry. Exceptions to these examples exist only in theoretical proposals. Here we predict and show experimentally that light can be perfectly confined in a patterned dielectric slab, even though outgoing waves are allowed in the surrounding medium. Technically, this is an observation of an ‘embedded eigenvalue’—namely, a bound state in a continuum of radiation modes—that is not due to symmetry incompatibility. Such a bound state can exist stably in a general class of geometries in which all of its radiation amplitudes vanish simultaneously as a result of destructive interference. This method to trap electromagnetic waves is also applicable to electronic and mechanical waves.United States. Army Research Office (Institute for Soldier Nanotechnologies under contract no. W911NF-07-D0004)United States. Department of Energy (grant no. DE-SC0001299)National Science Foundation (U.S.) (NSF grant no. DMR-0819762

[Review] Matthew Birchwood (2007) Staging Islam in England: drama and culture, 1640-1685

Matthew Birchwood. Staging Islam in England: Drama and Culture, 1640–1685. Pp. viii + 200. Boydell & Brewer Studies in Renaissance Literature 21. Cambridge: D.S. Brewer, 200

Dynamic particle tracking reveals the ageing temperature of a colloidal glass

Understanding glasses is considered to be one of the most fundamental problems in statistical physics. A theoretical approach to unravel their universal properties is to consider the validity of equilibrium concepts such as temperature and thermalization in these out-of-equilibrium systems. Here we investigate the autocorrelation and response function to monitor the aging of a colloidal glass. At equilibrium, all the observables are stationary while in the out-of-equilibrium glassy state they have an explicit dependence on the age of the system. We find that the transport coefficients scale with the aging-time as a power-law, a signature of the slow relaxation. Nevertheless, our analysis reveals that the glassy system has thermalized at a constant temperature independent of the age and larger than the bath, reflecting the structural rearrangements of cage-dynamics. Furthermore, a universal scaling law is found to describe the global and local fluctuations of the observables.Comment: 33 pages, 12 figure