Abstract: Aspects of the present disclosure are directed to apparatuses and methods involving nanowires having junctions therebetween. As consistent with one or more embodiments, an apparatus includes first and second sets of nanowires, in which the second set overlaps the first set. The apparatus further includes a plurality of nanowire joining recrystallization junctions, each junction including material from a nanowire of the first set that is recrystallized into an overlapping nanowire of the second set.

Abstract: Aspects of the present disclosure are directed to apparatuses and methods involving nanowires having junctions therebetween. As consistent with one or more embodiments, an apparatus includes first and second sets of nanowires, in which the second set overlaps the first set. The apparatus further includes a plurality of nanowire joining recrystallization junctions, each junction including material from a nanowire of the first set that is recrystallized into an overlapping nanowire of the second set.

Abstract: A tunable super-lens (TSL) for nanoscale optical sensing and imaging of bio-molecules and nano-manufacturing utilizes negative-index materials (NIMs) that operate in the visible or near infrared light. The NIMs can create a lens that will perform sub-wavelength imaging, enhanced resolution imaging, or flat lens imaging. This new TSL covers two different operation scales. For short distances between the object and its image, a near-field super-lens (NFSL) can create or enhance images of objects located at distances much less than the wavelength of light. For the far-zone, negative values are necessary for both the permittivity ? a permeability ?. While well-structured periodic meta-materials, which require delicate design and precise fabrication, can be used, metal-dielectric composites are also candidates for NIMs in the optical range. The negative-refraction in the composite films can be made by using frequency-selective photomodification.

Abstract: An object is disposed such that the apparatus is between the object and an observer. The appearance of the object is altered and, in the limit, the object cannot be observed, and the background appears unobstructed. The apparatus is formed of a metamaterial where the properties of the metamaterial are varied as a function of distance from the interfaces. The metamaterial may be fabricated as a composite material having a dielectric component and inclusions of particles of sub-wavelength size, and may also include a gain medium.

Abstract: A tunable super-lens (TSL) for nanoscale optical sensing and imaging of bio-molecules and nano-manufacturing utilizes negative-index materials (NIMs) that operate in the visible or near infrared light. The NIMs can create a lens that will perform sub-wavelength imaging, enhanced resolution imaging, or flat lens imaging. This new TSL covers two different operation scales. For short distances between the object and its image, a near-field super-lens (NFSL) can create or enhance images of objects located at distances much less than the wavelength of light. For the far-zone, negative values are necessary for both the permittivity ? a permeability ?. While well-structured periodic meta-materials, which require delicate design and precise fabrication, can be used, metal-dielectric composites are also candidates for NIMs in the optical range. The negative-refraction in the composite films can be made by using frequency-selective photomodification.

Abstract: An apparatus and method of cloaking is described. An object to be cloaked is disposed such that the cloaking apparatus is between the object and an observer. The appearance of the object is altered and, in the limit, the object cannot be observed, and the background appears unobstructed. The cloak is formed of a metamaterial where the properties of the metamaterial are varied as a function of distance from the cloak interfaces. The metamaterial may be fabricated as a composite material having a dielectric component and inclusions of particles of sub-wavelength size, and may also include a gain medium.

Abstract: An apparatus and method of cloaking is described. An object to be cloaked is disposed such that the cloaking apparatus is between the object and an observer. The appearance of the object is altered and, in the limit, the object cannot be observed, and the background appears unobstructed. The cloak is formed of a metamaterial where the properties of the metamaterial are varied as a function of distance from the cloak interfaces, and the permittivity is less than unity. The metamaterial may be fabricated as a composite material having a dielectric component and inclusions of particles of sub-wavelength size, so as to have a permeability substantially equal to unity.