Second-harmonic generation in nonlinear left-handed metamaterials

We study the second-harmonic generation in left-handed metamaterials with a quadratic nonlinear response. We demonstrate a novel type of the exact phase matching between the backward propagating wave of the fundamental frequency and the forward propagating wave of the second harmonics. We show that this novel parametric process can convert a surface of the left-handed metamaterial into an effective mirror totally reflecting the second harmonics generated by an incident wave. We derive and analyze theoretically the coupled-mode equations for a semi-infinite nonlinear metamaterial. We also study numerically the second-harmonic generation by a metamaterial slab of a finite thickness, and reveal the existence of multistable nonlinear effects.Comment: 6 pages, 6 figure

On the applicability of non-resonant artificial diamagnetics

Artificial diamagnetics are prominent for achieving extraordinarily strong diamagnetism in a wide frequency range. However, as far as the magnetic fields outside the artificial medium are concerned, bulk conductors show a very similar pattern. The question arises whether the complicated internal structure of artificial diamagnetics can, to this end, be replaced by a simpler object. We analyse the figure of merit for the application of diamagnetics in magnetic levitation, and show that for an electrically small body, any internal structuring makes the figure of merit worse than that of a simple conducting object.Comment: 5 pages, 5 figure

Vector circuit theory for spatially dispersive uniaxial magneto-dielectric slabs

We present a general dyadic vector circuit formalism, applicable for uniaxial magneto-dielectric slabs, with strong spatial dispersion explicitly taken into account. This formalism extends the vector circuit theory, previously introduced only for isotropic and chiral slabs. Here we assume that the problem geometry imposes strong spatial dispersion only in the plane, parallel to the slab interfaces. The difference arising from taking into account spatial dispersion along the normal to the interface is briefly discussed. We derive general dyadic impedance and admittance matrices, and calculate corresponding transmission and reflection coefficients for arbitrary plane wave incidence. As a practical example, we consider a metamaterial slab built of conducting wires and split-ring resonators, and show that neglecting spatial dispersion and uniaxial nature in this structure leads to dramatic errors in calculation of transmission characteristics.Comment: 11 pages, 6 figures, submitted to Journal of Electromagnetic Waves and Application

Daily System Check of Electronic Position Systems

The use of electronic navigation systems onboard NOS survey vessels necessitates one or more daily system checks to ensure the operational precision of the systems. In most instances, a position fix by visual methods is used for the daily check. The paper will first establish precision estimates for four fundamental measurements used in visual fixes and then present a discussion of six basic visual methods for daily system checks. The visual methods will be examined for their individual merits, drawbacks and estimated precision

A New Brain (February 27-28, March 5-7, 2015)

Program for A New Brain (February 27-28, March 5-7, 2015). To view the photos from this production of A New Brain, please click here

Loan Participations and the Savings and Loan Association: A Sleeping Giant Stirs

Savings institutions have believed themselves to be secure in their mortgage trading practices, but recent failures of financial institutions and the entry into the mortgage market of non-regulated, non-banking entities have prompted some much needed re-examination of the real risks and the character of the legal relationships which arise from such transactions. This article shall identify those risks, particularly the insolvency of the originating lender, and the resulting consequences which may be visited upon the investing savings institutions

Nonlinear magnetoinductive waves and domain walls in composite metamaterials

We describe novel physics of nonlinear magnetoinductive waves in left-handed composite metamaterials. We derive the coupled equations for describing the propagation of magnetoinductive waves, and show that in the nonlinear regime the magnetic response of a metamaterial may become bistable. We analyze modulational instability of different nonlinear states, and also demonstrate that nonlinear metamaterials may support the propagation of domain walls (kinks) connecting the regions with the positive and negative magnetization.Comment: 5 pages, 5 figure

Sunday in the Park with George

Inspired by George Seurat\u27s painting Sunday Afternoon on the Island of Le Grand Jatte, this is a play that in the first act contrasts the artist\u27s ability to organize and control his work and his inability to do either with his life. The second act is a second artist named George, Seurat\u27s grandson, trying to come to terms with similar issues. This play opened on October 22, 1999 and was reviewed in The Plain Dealer on October 28, 1999.https://collected.jcu.edu/plays/1119/thumbnail.jp

Structural tunability in metamaterials

We propose a novel approach for efficient tuning of the transmission characteristics of metamaterials through a continuous adjustment of the lattice structure, and confirm it experimentally in the microwave range. The concept is rather general and applicable to various metamaterials as long as the effective medium description is valid. The demonstrated continuous tuning of metamaterial response is highly desirable for a number of emerging applications of metamaterials including sensors, filters, switches, realizable in a wide frequency range