A general overview of slow light waveguide structures made of negative metamaterials is presented. We discuss the
conditions and the parameter space to achieve zero total energy flow and zero group velocity due to the degeneracy of
forward and backward waves in waveguides cladded with single negative metamaterials. Absorptive loss plays a
severely limiting role and can prevent achieving the zero group velocity condition. Gain can be introduced either in
dielectric or negative metamaterials to restore the zero group velocity condition. This type of slow light waveguide has a
large delay bandwidth product and is suitable for use in integrated optoelectronic circuits.
Super-resolution imaging using a three-dimensional metamaterials nanolens has been recently reported [B. D. F.
Casse et al. Appl. Phys. Lett. 96, 023114 (2010)]. This nanolens, consisting of bulk gold nanowires embedded
in alumina template, can transport with low-loss object details down to λ/4 (λ, wavelength) length scales, over
significant distances of the order of 6λ. Here, we present validation of the super-resolution imaging by the nanolens
through extensive control experiments. We also analytically show that the nanowire array medium supports a
quasi transverse electromagnetic mode (TEM) with flat isofrequency contours, which is a requirement for super-resolution
imaging. We numerically compute the optical transfer function to quantify the imaging quality of
the lens and show that the theoretical resolution of this nanolens is λ/5. Additionally, we demonstrate the
broadband nature of the lens in the spectral region 1510 nm to 1580 nm. Finally, imaging of a large object
(~ 52λ in diameter), with subwavelength features, is presented.
Planned in-situ radiosensitization may improve the therapeutic ratio of image guided 125I prostate brachytherapy.
Spacers used in permanent implants may be manufactured from a radiosensitizer-releasing polymer to deliver protracted
localized sensitization of the prostate. Such devices will have a limited drug-loading capacity, and the drug release
schedule that optimizes outcome, under such a constraint, is not known. This work determines the optimal elution
schedules for 125I prostate brachytherapy. The interaction between brachytherapy dose distributions and drug
distribution around drug eluting spacers is modeled using a linear-quadratic (LQ) model of cell kill. Clinical
brachytherapy plans were used to calculate the biologic effective dose (BED) for planned radiation dose distributions
while adding the spatial distributions of radiosensitizer while varying the temporal release schedule subject to a
constraint on the drug capacity of the eluting spacers. Results: The greatest increase in BED is achieved by schedules
with the greatest sensitization early in the implant. Making brachytherapy spacers from radiosensitizer eluting polymer
transforms inert parts of the implant process into a means of enhancing the effect of the brachytherapy radiation. Such
an approach may increase the therapeutic ratio of prostate brachytherapy or offer a means of locally boosting the
radiation effect without increasing the radiation dose to surrounding tissues.
Nanotechnology offers unique approaches to probe and control a variety of biological and medical processes that occur at nanometer length scales, and is expected to have a revolutionary impact on biology1 and medicine2. Nanomedicine is a new paradigm that seeks to exploit the use of nanotechnology in medicine. Among the various approaches within the nanomedicine paradigm, nanoparticles and nanotemplates offer some unique advantages as sensing, diagnostic, delivery, and image enhancement agents3,4. Several varieties of nanoparticles5 are available: polymeric nanoparticles6, metal nanoparticles7, liposomes8, micelles, quantum dots, dendrimers, magnetic nanoparticles9, and nanoassemblies10,11. All of these nanoparticles can play a major role in medicine, and especially in diagnosis and therapy of cancer12,13,14, cardiovascular diseases, and infectious diseases. To further the application of nanoparticles in disease diagnosis and therapy, it is important that the systems are stable, capable of being functionalized, biocompatible, and directed to specific target sites in the body after systemic administration. In this short review we discuss four areas of research carried out by the Nanomedicine Consortium using nanoparticles and nanotemplates to explore new approaches in nanotechnology for medical diagnosis, imaging and therapy.
Negative refraction and left-handed electromagnetism in a photonic crystal are demonstrated in waveguide and free space experiments at microwave frequencies. Precision control to achieve tailor-made refractive indices has been achieved. The negative refraction in these photonic crystals is shown to lead to imaging by a flat lens. We have also developed a generalized theory of flat lens imaging. These results promise potential applications in a variety of optical and microwave systems for communications and imaging.