We present a polarization-insensitive plasmonic photoconductive terahertz emitter that uses a two-dimensional array of nanoscale cross-shaped apertures as the plasmonic contact electrodes. The geometry of the cross-shaped apertures is set to maximize optical pump absorption in close proximity to the contact electrodes. The two-dimensional symmetry of the cross-shaped apertures offers a polariza...

The field of computational photography, and in particular the design and implementation of coded apertures, has yielded impressive results in the last years. In this paper we introduce perceptually-optimized coded apertures for defocused deblurring. We obtain near-optimal apertures by means of optimization, with a novel evaluation function that includes two existing image quality perceptual met...

This reaffirmation of teachers has been a leading factor in the development of recent strategies for school improvement The reports by the Carnegie Task Force and the Holmes Group are two prominent examples of proposals aimed specifically at problems within the teaching profession. These reports are significant in that they have helped place teaching squarely at the center of current educationa...

We define here a new symmetry operator called reciprocation. Apertures that remain unchanged afler reciprocation are called self-reciprocal, and have a number of unique properties. When excited suddenly by a voltage, a self-reciprocal aperture becomes an antenna. This antenna is an approximation to a TEM horn, to a lens IRA (TEM feed + lens), or to a reflector IRA (TEM feed + reflector). Becaus...

Microwave bandpass filter structure has been designed and fabricated by filling the periodically metallic apertures with dielectric particles. The microwave cannot transmit through the metallic subwavelength apertures. By filling the metallic apertures with dielectric particles, a transmission passband with insertion loss 2 dB appears at the frequency of 10-12 GHz. Both simulated and experiment...

We consider imaging strategies for synthetic aperture radar data collections that span a wide angular aperture. Most traditional radar imaging techniques are predicated on the assumption of isotropic point scattering mechanisms, which does not hold for wide apertures. We investigate point scattering center images for narrowband, wide angle data, and consider the effect of limited persistence on...

We revisit the far from equilibrium escape problem across a fluctuating potential barrier that is driven by asymmetric, unbiased dichotomous noise. Our closed analytical solution for arbitrary noise strengths reveals new aspects of the so-called ‘‘resonant-activation’’ effect and leads to interesting implications regarding far from equilibrium or externally controlled chemical reaction processe...