Four types of plasmonic lenses for the purpose of superfocusing designed on the bases of approximate negative refractive index concept, subwavelength metallic structures, waveguide mode were introduced, and curved chains of nanoparticles, respectively, were introduced. Imaging mechanism, fabrication, and characterization issues were presented. Theoretical analyses of the illumination with different polarization states on focusing performance of the plasmonic lenses were given also. In addition, a hybrid Au-Ag plasmonic lens with chirped slits for the purpose of avoiding oxidation of Ag film was presented.

The Lower Lufeng Formation (Lower Jurassic: ?Hettangian-?Sinemurian) of Yunnan Province, China, has yielded an important and diverse fauna of terrestrial vertebrates that is dominated by early sauropodomorph dinosaurs (prosauropods and basal sauropods). Nevertheless, few of these animals have been studied in detail, undermining their potential significance in understanding sauropodomorph phylogeny, palaeobiology, and palaeoecology. Here, we present a detailed re-description of the cranial osteology of Yunnanosaurus huangi Young, 1942 and propose an emended diagnosis for this taxon on the basis of numerous autapomorphic characters (including an expanded internarial bar, unusual midline cranial bosses, and the possession of elongate maxillary tooth crowns lacking marginal serrations). Incorporation of these novel anatomical data into existing phylogenetic analyses of sauropodomorph interrelationships substantially affects the resolution, length, and topologies of the trees recovered. Although the phylogenetic position of Yunnanosaurus remains labile, these new analyses undermine previous suggestions that the former was the sister taxon of the southern African prosauropod Massospondylus . Several features of the skull of Yunnanosaurus (small external nares, cranial bosses, tooth crown morphology, and the lack of maxillary foramina) indicate that the palaeobiology of Yunnanosaurus may have been rather different from that of other prosauropods and basal sauropods, although more detailed functional studies and better material are needed to confirm this suggestion.

Low-energy-ion bombardment of semiconductors can lead to the development of complex and diverse nanostructures. Of particular interest in these structured surfaces is the formation of highly ordered patterns whose optical, electronic, and magnetic properties are different from those of bulk materials and might find technological uses. [1][2][3][4][5] Compared to the low efficiency of lithographic methods for mass production, this self-organized approach offers a new route for fabrication of ordered patterns over large areas in a short processing time on the nanometer scale, beyond the limits of lithography. [1,4] This technique is based on the morphological instability of a sputtered surface driven by a kinetic balance between roughening and smoothing. [6,7] Thus mechanisms that control the species concentration on the surface can make contributions to structure formation. [3,[7][8][9][10][11][12] It is now established that well-ordered quantum dots can be generated on the surface of semiconductors (Si, Ge, GaSb) under certain irradiation conditions. [1,13,14] For a long time it has been expected that the instability of a surface can also lead to well-ordered hole formation. However, to date experimental observation of such features has been lacking. In this Communication, we report that a hexagonally ordered, honeycomb-like structure of holes 35 nm across and 45 nm apart on the Ge surface can be formed under focused ion beam (FIB) bombardment at normal incidence. The structured Ge fabricated by FIB bombardment shows a high surface area and a considerably blue-shifted energy gap. We found that interplay between ion sputtering, redeposition, viscous flow, and surface diffusion is responsible for ordered pattern formation. Simulations of the evolution of the surface morphology on the basis of the damped Kuramoto-Sivashinsky (DKS) growth model have been performed to facilitate the interpretation of the experimental findings. [15][16][17][18][19] As an indirect energy-gap semiconductor, germanium is a poor light emitter, which makes it challenging to create efficient Ge-based light-emitting devices. Significant effort has been devoted to the development of the optical properties of Ge based on changing the surface morphology.[20] In the work reported here, we focused on the use of ion beam radiation to fabricate nanostructures on the Ge surface.The ion-induced nanostructures were fabricated on commercially available Ge with (100) orientation by FIB bombardment. Under normal bombardment with ion energy greater than 5 keV, worm-like structures were developed on Ge surface with large aspect ratio. When the energy was 5 keV, however, highly ordered hole arrays could be achieved. Figure 1 shows scanning electron microscopy (SEM) and atomic force microscopy (AFM) images of a typical nanohole pattern induced on a Ge(100) surface by 5 keV (Ga þ ) FIB bombardment for 5 min. A perfect hexagonal arrangement of holes is observed within domains of ca. 500 nm. Like polycrystalline structure, there are ''grain boundaries'' separati...

A plasmonic lens with metallic chirped circular nanoslits corrugated on Au film supported on quartz substrate for the purpose of superfocusing was put forth and fabricated by means of focused ion beam direct milling technique. Topography of the lens was imaged using an atomic force microscope. After that a near-field scanning optical microscope was employed for optical characterization of focusing performance of the lens. Our experimental results verify the focusing performance and further demonstrate that they are in agreement with the theoretical calculation results. Focusing performance is significantly improved in comparison to that of the non-chirped lens. The lenses are possible to be used for the applications of bioimaging, detection, and inspection in submicron scale resolution.

We report far-infrared absorption in directly doped self-organized InAs quantum dots. Photoluminescence spectra demonstrate a blue shift in peak intensity for increasing doping in the quantum dots. Far-infrared absorption measurements using a Fourier transform infrared spectrometer show absorption in the range of 13–18 μm for quantum dots with Al0.15Ga0.85As and GaAs as the barrier material.