We review the relations between a family of domain-wall solutions to M-theory and gravitational instantons with special holonomy. When oxidized into the maximal-dimension parent supergravity, the transverse spaces of these domain walls become cohomogeneity-one spaces with generalized Heisenberg symmetries and a homoth-etic conformal symmetry. These metrics may also be obtained as scaling limits...

We report a general framework capable of describing the focusing of electromagnetic waves with spatially varying coherence and polarization properties in optical systems of arbitrary numerical aperture and Fresnel number. We also investigate the reduction of the dimensionality of the requisite integrals by use of a coherent mode expansion. We find that coherent mode expansions treating each com...

We have integrated lithographically patterned VO2 thin films grown by pulsed laser deposition with silicon-on-insulator photonic waveguides to demonstrate a compact in-line absorption modulator for use in photonic circuits. Using single-mode waveguides at lambda=1550 nm, we show optical modulation of the guided transverse-electric mode of more than 6.5 dB with 2 dB insertion loss over a 2-micro...

While ray optics is a valid model for many multimode optical systems, it cannot capture diffraction and interference phenomena which may be required, for example, in calculating speckle propagation in multimode fiber. Wave optics includes the effect of interference and diffraction, but it is usually much more costly computationally. We show how to bridge the gap between ray and wave optics by u...

We demonstrate a dual-band two-mode (de)-multiplexer based on tapered asymmetric directional coupler (ADC). The working principle of the device relies conversion fundamental transverse electric (TE0) mode to first order (TE1) mode. A phase-matching condition is applied across O- and C-bands broaden operation wavelength device. Measurement performed division multiplexing (MDM) link formed by bac...

If a laser beam is to have radial transverse polarization, the transverse electric must vanish on the symmetry axis, which is charge free in vacuum. However, we can expect a nonzero longitudinal electric field on the axis, noting that the projections onto the axis of the electric field vectors of rays all have the same sign, as shown in Fig. 2a. This contrasts with the case of linearly polarize...

We demonstrate the first electric field induced transverse deflection of a single-crystal, free-standing ZnO microbelt as a result of converse piezoelectric effect. For a microbelt growing along the c-axis, a shear stress in the a-c plane can be induced when an electric field E is applied along the a-axis of the wurtzite structure. As amplified by the large aspect ratio of the microbelt that gr...

We predict the existence of transverse electric (TE) plasmons in bilayer graphene. We find that their plasmonic properties are much more pronounced in bilayer than in monolayer graphene, in a sense that they can get more localized at frequencies just below ħω = 0.4 eV for adequate doping values. This is a consequence of the perfectly nested bands in bilayer graphene which are separated by ∼ 0.4...