Stimulated Stokes emission has been observed from silicon crystals doped by antimony donors when optically excited by radiation from a tunable infrared free electron laser. The photon energy of the emission is equal to the pump photon energy reduced by the energy of the intervalley transverse acoustic (TA) g phonon in silicon (approximately 2.92 THz). The emission frequency covers the range of ...

The absorption spectrum represents an important aspect of single semiconductor nanocrystals (NCs), revealing the morphology and orientation of the NCs. By conducting quantitative photoluminescence excitation spectroscopy based on a single-photon counting method, we succeed in clarifying the absorption cross-section spectrum of neutral excitons in single CdSe/ZnS NCs. With the values of the abso...

ing their permission to publish these cases. The histopathological examinations were performed at the National CJD Surveillance Unit by Dr James Ironside. Contributors: RdeS, JP, and DH raised the possibility of using single photon emission computed tomography as a diagnostic “pointer” in new variant Creutzfeldt-Jakob disease, and RdeS wrote the paper. AR, MT, and MZ discussed the core concept ...

We present a simple method of removing the singularities associated with soft photon emission to all orders in perturbation theory through exponentiation, while keeping a consistent description of hard photon emission. We apply this method to the process e + e ? ! + ? + n where we include both Z 0 and exchange and retain the muon mass dependence. The photonic radiation is allowed to be radiated...

The STM-electroluminescence technique is shown to be a valuable tool for characterizing optoelectronic properties and understanding structure-function relationships in heterogeneous or disordered materials on nanometer length scales. The intensity of photon emission induced by tunneling electrons from rough Au films is found to depend on the surface feature size. This size-dependent photon emis...

Ultra-weak photon emission (UPE) of a living system received scientific attention because of its potential for monitoring increased levels of reactive oxygen species (ROS) in the pathogenesis of rheumatoid arthritis (RA). In this study, a highly sensitive cryogenic charge-coupled device (CCD) camera was used to monitor in a RA mouse model the photon emission both without and with luminol. For t...

Solar-energy conversion usually takes one of two forms: the 'quantum' approach, which uses the large per-photon energy of solar radiation to excite electrons, as in photovoltaic cells, or the 'thermal' approach, which uses concentrated sunlight as a thermal-energy source to indirectly produce electricity using a heat engine. Here we present a new concept for solar electricity generation, photon...

Controlled engineering of isolated solid state quantum systems is one of the most prominent goals in modern nanotechnology. In this letter we demonstrate a previously unknown quantum system namely silicon carbide tetrapods. The tetrapods have a cubic polytype core (3C) and hexagonal polytype legs (4H)--a geometry that creates spontaneous polarization within a single tetrapod. Modeling of the te...

We study amplitude zeros in radiative decay processes with a photon or a gluon emission of all possible scalar particles(e.g. scalar leptoquarks) which may interact with the usual fermions in models beyond the standard model. For the decays with a photon emission, the amplitudes clearly exhibit the factorization property and the differential decay rates vanish at specific values of a certain va...

Emission computed tomography (ECT) is a technology for medical imaging whose importance is increasing rapidly. There is a growing appreciation for the value of the functional (as opposed to anatomical) information that is provided by ECT and there are significant advancements taking place, both in the instrumentation for data collection, and in the computer methods for generating images from th...