Engineering metamaterials with tunable resonances from mid-infrared to near-infrared wavelengths could have far-reaching consequences for chip based optical devices, active filters, modulators, and sensors. Utilizing the metal-insulator phase transition in vanadium oxide (VO(2)), we demonstrate frequency-tunable metamaterials in the near-IR range, from 1.5 - 5 microns. Arrays of Ag split ring resonators (SRRs) are patterned with e-beam lithography onto planar VO(2) and etched via reactive ion etching to yield Ag/VO(2) hybrid SRRs. FTIR reflection data and FDTD simulation results show the resonant peak position red shifts upon heating above the phase transition temperature. We also show that, by including coupling elements in the design of these hybrid Ag/VO(2) bi-layer structures, we can achieve resonant peak position tuning of up to 110 nm.

Abitract A nonintercepting omittance monitor b a helpful device for measuring and improving particle beams ia acceler ator* and storage rings as it allows continuous monitoring of the beam's distribution in phase space, and perhaps closed loop computer control of the distributions. Stripliae position moni tors are being investigated for use as nonintercepting emittanee monitors for a beam focused by a FODO array in the first 100 meters of our linear accelerator. The technique described hart uses the signal from the four stripline probes of a single positioa monitor to measure the quadrupole mode of the wall currant la the beam pipe. This current is a function of the quadripole moment of the beam, e>|-oj. In general, six independent maaau rements of the quadrupole moment are necessary to determine the beam emittance. This technique is dependent on the char* acteristically large variations of o\-

We discuss a time-of-flight measurement of the speed of light which is inexpensive to build, has an experimental design completely accessible to students with a rudimentary knowledge of interference, and consistently produces values for c with errors of less than 1%. Students at the sophomore level can use the same apparatus to achieve uncertainties on the order of 0.25%.

It is well known from optics that the speed of light in a transparent medium is reduced by a factor of n (the index of refraction) as compared with vacuum. Maxwell’s electrodynamics provides a simple account of this phenomenon, and relates n to the electric susceptibility of the material. But the conventional analysis does little to illuminate the mechanism involved. This paper offers some elucidation of the ‘‘miracle’’ by which the radiation from many induced molecular dipoles conspires to produce a single wave propagating at the reduced speed.

Abstracttwren the buncher and the accelerator since space charge forces would cause the bunch to debunch rapidly in the absence of a comprrssing longitudinal electric field. The buncher is phased so that the bunch enters the accelerator centered on the phase focusing longitudinal electric Geld null. This causes the bunch to undergo an additional factor of 3 phase compression as it drifts back to the accelerating crest in the first meter of the 3 meter section. A cut-off iris between the buncher and accclcrator section permits independent adjustment of phase and RF power level for each.