Nanophotonic boost of intermolecular energy transfer

We propose a scheme for efficient long-range energy transfer between two distant light emitters separated by more than one wavelength of light, i.e. much beyond the classical Forster radius. A hybrid nanoantenna-waveguide system mediates the transmission of energy, showing enhancements up to 10^8 as compared to vacuum. Our model shows how energy transfer in nanostructured media can be boosted, beyond the simple donor Purcell enhancement, and in particular for large donor-acceptor separations. The scheme we propose connects realistic emitters and could lead to practical on-chip implementations.Comment: 9 pages, 4 figure

KM3NeT:a large underwater neutrino telescope in the Mediterranean Sea

High energy neutrinos produced in astrophysical processes will allow for a new way of studying the universe. In order to detect the expected flux of high energy neutrinos from specific astrophysical sources, neutrino telescopes of a scale of a km^3 of water will be needed. A Northern Hemisphere detector is being proposed to be sited in a deep area of the Mediterranean Sea. This detector will provide complimentary sky coverage to the IceCube detector being built at the South Pole. The three neutrino telescope projects in the Mediterranean (ANTARES, NEMO and NESTOR) are partners in an effort to design, and build such a km^3 size neutrino telescope, the KM3NeT. The EU is funding a 3-year Design Study; the status of the Design Study is presented and some technical issues are discussed.Comment: 4 pages, 3 figures, Prepared for the 10th International Conference on Astroparticle and Underground Physics (TAUP 2007), Sendai, Japan, 11-15 Sep 200

Acellular dermal regeneration template for soft tissue reconstruction of the digits.

PURPOSE: Trauma to the digits often leaves soft tissue defects with exposed bone, joint, and/or tendon that require soft tissue replacement. The objective of this study was to evaluate the effectiveness of acellular dermal regeneration template combined with full-thickness skin grafting for soft tissue reconstruction in digital injuries with soft tissue defects. METHODS: Acellular dermal regeneration template was used to reconstruct digital injuries with exposed bone, joint, tendon, and/or hardware not amenable to treatment with healing by secondary intention, rotation flaps, or primary skin grafts. Acellular dermal regeneration template was applied to 21 digits in 17 patients. Nineteen digits had exposed bone, 8 digits had exposed tendon, 6 digits had exposed joints, and 2 digits had exposed hardware. The acellular dermal regeneration template was sutured over the soft tissue defect. Over 3 weeks, a neodermis formed. The superficial silicone layer of the acellular dermal regeneration template was removed, and the digits received full-thickness epidermal autografting with cotton bolster. RESULTS: The duration of postoperative follow-up extended to a minimum of 12 months. For the injury sites where acellular dermal regeneration template was applied, the total area of application ranged from 1 cm(2) to 24 cm(2), with the largest individual site measuring 12 cm(2). Twenty of 21 digits demonstrated 100% incorporation of the acellular dermal regeneration template skin substitute. One digit that had sustained multilevel trauma developed necrosis requiring revision amputation. Full-thickness epidermal autografting was performed an average of 24 days after acellular dermal regeneration template skin substitute application and demonstrated a 100% take in 16 of 20 digits and partial graft loss of 15% to 25% in 4 of 20 digits that did not require further treatment. CONCLUSIONS: Acellular dermal regeneration template combined with secondary full-thickness skin grafting is an effective method of skin reconstruction in complex digital injuries with soft tissue defects involving exposed bone, tendon, and joint. The neodermis increases tissue bulk and facilitates epidermal autografting with digital injuries that otherwise would require flap coverage or skeletal shortening of the digit. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV

Cavity Quantum Electrodynamics with Anderson-localized Modes

A major challenge in quantum optics and quantum information technology is to enhance the interaction between single photons and single quantum emitters. Highly engineered optical cavities are generally implemented requiring nanoscale fabrication precision. We demonstrate a fundamentally different approach in which disorder is used as a resource rather than a nuisance. We generate strongly confined Anderson-localized cavity modes by deliberately adding disorder to photonic crystal waveguides. The emission rate of a semiconductor quantum dot embedded in the waveguide is enhanced by a factor of 15 on resonance with the Anderson-localized mode and 94 % of the emitted single-photons couple to the mode. Disordered photonic media thus provide an efficient platform for quantum electrodynamics offering an approach to inherently disorder-robust quantum information devices

Strong enhancement of extremely energetic proton production in central heavy ion collisions at intermediate energy

The energetic proton emission has been investigated as a function of the reaction centrality for the system 58Ni + 58Ni at 30A MeV. Extremely energetic protons (EpNN > 130 MeV) were measured and their multiplicity is found to increase almost quadratically with the number of participant nucleons thus indicating the onset of a mechanism beyond one and two-body dynamics.Comment: 5 pages, 2 figures, submitted to Physical Review Letter

Correlation between OCVD carrier lifetime vs temperature measurements and reverse recovery behavior of the body diode of SiC power MOSFETs

The reverse recovery (RR) behavior of SiC MOSFET body diode is of great importance in power application, where these devices are used in a wide range of operating temperatures. The carrier lifetime in the drift region varies with temperature, and it heavily affects the tailoring of the RR current, opening reliability issues related to the RR voltage amplitude and to possible anomalous voltage oscillations during the recovery. From the users' point of view, it would be useful to have a simple technique able to give predictive information about the body diode RR behavior of commercial devices over the whole range of working temperatures. An experimental-simulation approach is presented in this paper to correlate the carrier lifetime measured by simple OCVD measurements versus temperature with the RR behavior of the body diode, that can be useful at the design stage of power converters. Simulations of the body diode reverse-recovery are performed for a wide range of carrier lifetimes. This allows to estimate the effect of changes of carrier lifetime with temperature on the body diode switching transients. Preliminary results obtained with a 1700 V/5A commercial MOSFET are shown