A new Super-Kamiokande (SK) search for Supernova Relic Neutrinos (SRNs) was conducted using 2853 live days of data. Sensitivity is now greatly improved compared to the 2003 SK result, which placed a flux limit near many theoretical predictions. This more detailed analysis includes a variety of improvements such as increased efficiency, a lower energy threshold, and an expanded data set. New combined upper limits on SRN flux are between 2.8 and 3.0νe cm −2 s −1 > 16 MeV total positron energy (17.3 MeV Eν).
We have searched for proton decay via p → νK + using Super-Kamiokande data from April 1996 to February 2013, 260 kiloton·year exposure in total. No evidence for this proton decay mode is found. A lower limit of the proton lifetime is set to τ/B(p → νK + ) > 5.9 × 10 33 years at 90% confidence level.
Optoelectronic devices have long benefited from structuring in multiple dimensions on microscopic length scales. However, preserving crystal epitaxy, a general necessity for good optoelectronic properties, while imparting a complex three-dimensional structure remains a significant challenge. Three-dimensional (3D) photonic crystals are one class of materials where epitaxy of 3D structures would enable new functionalities. Many 3D photonic crystal devices have been proposed, including zero-threshold lasers, low-loss waveguides, high-efficiency light-emitting diodes (LEDs) and solar cells, but have generally not been realized because of material limitations. Exciting concepts in metamaterials, including negative refraction and cloaking, could be made practical using 3D structures that incorporate electrically pumped gain elements to balance the inherent optical loss of such devices. Here we demonstrate the 3D-template-directed epitaxy of group III-V materials, which enables formation of 3D structured optoelectronic devices. We illustrate the power of this technique by fabricating an electrically driven 3D photonic crystal LED.
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