Observation of abruptly autofocusing waves

We report on the experimental observation of abruptly autofocusing waves. This interesting family of wave packets has been realized by using a radially symmetric Airy intensity distribution. As demonstrated in our experiments, these waves can exhibit unusual features, such as the ability to autofocus by following a parabolic trajectory toward their focus.     

Pre-engineered abruptly autofocusing beams

We introduce a new family of (2+1)D light beams with pre-engineered abruptly autofocusing properties. These beams have a circularly symmetric input profile that develops outward of a dark disk and oscillates radially as a sublinear-chirp signal, creating a series of concentric intensity rings with gradually decreasing width. The light rays involved in this process form a caustic surface of revolution that bends toward the beam axis at an acceleration rate that is determined by the radial chirp itself. The collapse of the caustic on the axis leads to a large intensity buildup right before the intended focus. This ray-optics interpretation provides valuable insight into the dynamics of abruptly autofocusing waves.     

Superresolution via enhanced evanescent tunneling

We here propose the concept of enhanced evanescent tunneling (EET). Our analysis indicates that by means of a suitable control field, the transmission of evanescent waves across a forbidden gap can be enhanced by several orders of magnitude-well beyond the ordinary frustrated total internal reflection case. We show how such a phenomenon can be used to probe both the amplitude and phase of the evanescent portion of the angular spectrum, thereby allowing target superresolution. In principle EET can be manifested in other areas of physics where wave tunneling is involved.     

Synthesis and characterization of gadolinium nanostructured materials with potential applications in magnetic resonance imaging,neutron-capture therapy and targeted drug delivery

Two Gadolinium nanostructured materials, Gd₂(OH)₅NO₃ nanoparticles and Gd(OH)₃ nanorods, were synthesized and extensively characterized by various techniques. In addition to the potential use of Gd₂(OH)₅NO₃ in magnetic resonance imaging (MRI) and Neutron-capture therapy (NCT) application, it could also be used in targeted drug delivery. An antibiotic (nalidixic acid), two amino acids (aspartic and glutamic acid), a fatty acid and a surfactant (SDS) were intercalated in the nanoparticles. The surface of the nanoparticles was modified with folic acid in order to be capable of targeted delivery to folate receptor expressing sites, such as tumor human cells.