APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

19 Mar 2012

Volume 100, Issue 12, Articles (12xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 100, 121101 (2012); http://dx.doi.org/10.1063/1.3693413 (4 pages)

Jolly Xavier, Raktim Dasgupta, Sunita Ahlawat, Joby Joseph, and Pradeep Kumar Gupta
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Free-space carpet-cloak based on gradient index photonic crystals in metamaterial regime

Ming Yin, Xiao Yong Tian, Hao Xue Han, and Di Chen Li

Appl. Phys. Lett. 100, 124101 (2012); http://dx.doi.org/10.1063/1.3696040 (3 pages) | Cited 2 times

Online Publication Date: 20 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A free-space broadband carpet-cloak, designed based on transformations optics and quasi-conformal mapping, was realized with all-dielectric gradient index rod-connected diamond-structured photonic crystals (PCs) in metamaterial regime. Complex three-dimensional sample with smooth continuous changing unit cells was fabricated precisely by stereolithography (SL) using photo-curable resin. Thus, by gradually varying the unit cell constitutive parameters of the diamond-based PCs with nearly isotropic properties, the required complex spatial distribution of the refractive index profile was ideally achieved to reduce the scattering of the electromagnetic wave. The non-resonant property of the sub-wavelength PCs unit cell resulted in broad bandwidth and relatively low loss.
Show PACS
42.79.Ry Gradient-index (GRIN) devices
42.70.Qs Photonic bandgap materials
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
84.40.-x Radiowave and microwave (including millimeter wave) technology

X-ray phase imaging with a paper analyzer

Kaye S. Morgan, David M. Paganin, and Karen K. W. Siu

Appl. Phys. Lett. 100, 124102 (2012); http://dx.doi.org/10.1063/1.3694918 (4 pages) | Cited 3 times

Online Publication Date: 21 March 2012

Full Text: Read Online (HTML) | Download PDF

multimedia

Show Abstract
We present a simple x-ray phase imaging method that utilizes the sample-induced distortion of a high contrast random intensity pattern to quantitatively retrieve the two-dimensional phase map at the exit surface of a coherently illuminated sample. This reference pattern is created by placing a sheet of sandpaper in the x-ray beam, with the sample-induced distortion observed after propagation to the detector, a meter downstream. Correlation analysis comparing a single “sample and sandpaper” image to a reference “sandpaper only” image produces two sensitive differential phase contrast images, giving the sample phase gradient in vertical and horizontal directions. These images are then integrated to recover the projected phase depth of the sample. The simple experimental set-up, retention of flux, and the need for only a single sample image per reconstruction suggest that this method is of value in imaging a range of dynamic processes at both synchrotron and laboratory x-ray sources.
Show PACS
87.59.-e X-ray imaging
Author Select

Effective permeability of a metamaterial: Against conventional wisdom

R. R. A. Syms and L. Solymar

Appl. Phys. Lett. 100, 124103 (2012); http://dx.doi.org/10.1063/1.3696075 (3 pages)

Online Publication Date: 22 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A method for finding the effective permeability of metamaterials is presented, based on the interaction between electromagnetic and magnetoinductive waves. Assuming a coupled circuit model for the interaction, a dispersion equation is derived that exhibits two types of bandgaps, one leading to complex solutions and the other to purely evanescent waves. Although losses are disregarded, the effective permeability (in contrast to established theories) is shown to have an imaginary part in part of the stop band, while its real part remains finite in both the pass band and the stop band.
Show PACS
42.70.-a Optical materials

Electrostatically coupled vibration modes in unimorph complementary microcantilevers

V. Lebedev, N. Heidrich, F. Knöbber, R. E. Sah, W. Pletschen, B. Raynor, V. Polyakov, V. Cimalla, and O. Ambacher

Appl. Phys. Lett. 100, 124104 (2012); http://dx.doi.org/10.1063/1.3697647 (4 pages) | Cited 2 times

Online Publication Date: 22 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
To extend the tuning capabilities of radio frequency devices, coupled microelectromechanical systems are often employed. In this letter, we demonstrate piezoelectrically actuated, electrically tuneable resonator systems based on coupled micromechanical oscillators operating in a flexural vibration mode. The substantial enhancement in electrostatic coupling was achieved due to the implementation of lateral nanogaps of 100-200 nm between single resonator bars. This allows for resonator synchronization and precise system frequency tuning by over a factor of two, relative to its initial value. Additionally, a simple electro-mechanical model has been developed to describe the dynamic behavior of the electrostatically coupled oscillators.
Show PACS
84.30.Ng Oscillators, pulse generators, and function generators
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
85.50.-n Dielectric, ferroelectric, and piezoelectric devices
84.40.Az Waveguides, transmission lines, striplines

Non-contacting characterization of the electrical and mechanical properties of rocks at submillimeter scales

Nathan S. Greeney and John A. Scales

Appl. Phys. Lett. 100, 124105 (2012); http://dx.doi.org/10.1063/1.3692576 (3 pages)

Online Publication Date: 23 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
At the meso and macro-scale, the connection between the elastic and the electromagnetic properties of granular materials such as rocks is complicated and involves, among other things, the chemical, mineralogical, and geometric features of the grains and their host medium. In the previous work, we showed how to perform rapid near-field millimeter wave scanning to obtain high-spatial resolution maps of the spatially varying dielectric permittivity of heterogeneous materials, including rocks. Here, we extend this concept to laser ultrasound and map the spatially varying mechanical properties of materials with similar resolution.
Show PACS
91.60.Pn Magnetic and electrical properties
91.55.-y Structural geology
91.60.Ba Elasticity, fracture, and flow
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close