We explore theoretically the principles that govern photon emission from single-molecule conductors carrying electric currents between metallic contacts. The molecule and contacts are represented by a generic tight-binding model. The electric current is calculated using Landauer theory and the pho-ton emission rate is obtained using Fermi's golden rule. The bias-dependence of the electronic str...

OBJECTIVES The proper nodal staging of non-small cell lung cancer is important for choosing the best treatment modality. Although computed tomography remains the first-line imaging test for the primary staging of lung cancer, its limitations for mediastinum nodal staging are well known. The aim of this study is to evaluate the accuracy of hybrid single-photon emission computed tomography and co...

The usual fluorescence behavior follows Stokes law, where exciting photons are of higher energy than emitted photons. Anti-Stokes processes usually concern emitted energies in excess of excited energies by only a few kT. These processes include anti-Stokes emission by the thermal bands or by the Raman effect. There are processes, however, in which emission photon energy exceeds excited photon e...

We report the influence of photonic stopgaps on two-photon excited emission from highly efficient nonlinear chromophores infiltrated into high-quality photonic crystals. We have observed a sharp decrease (filter effect) in emission within the frequency range and direction of the stopgap as well as sharp enhancement of the two-photon excited emission associated with the stopgap's edge. This effe...

We consider atomic system of Λ−type 3-level coupled to 2 mode fields, and derive an effective Maxwell-Bloch equation designed for two photon emission between two lower levels. We find axially symmetric, topologicaly stable soliton solutions made of condensed fields. Immediate implication of soliton formation to radiative neutrino pair emission is to enhance its rate larger than the usual ∝ N fa...

Radiative processes lead to important corrections to (e, e′p) experiments. While radiative corrections can be calculated exactly in QED and to a good accuracy also including hadronic corrections, these corrections cannot be included into data analyses to arbitrary orders exactly. Nevertheless consideration of multi-photon bremsstrahlung above the low-energy cut-off is important for many (e, e′p...

the aim of this article is to review the application of current imaging techniques used for the detection of viable myocardium. each technique is discussed briefly, and the more commonly used techniques are compared. the imaging techniques reviewed herein are dobutamine stress echocardiography, single photon emission tomography, magnetic resonance imaging, positron emission tomography with f-18...

this paper intends to compare the abilities of the two major imaging modalities in nuclear medicine imaging: positron emission tomography (pet) and single photon emission computed tomography (spect). the motivations are many-fold: (i) to gain a better understanding of the strengths and limitations of the two imaging modalities in the context of recent and ongoing developments in hardware and so...

We demonstrate experimentally two-photon transparency, achieved by current injection into a semiconductor quantum-well structure which exhibits two-photon emission. The two-photon induced luminescence is progressively reduced by the injected current, reaching the point of two-photon transparency-a necessary condition for semiconductor two-photon gain and lasing. These results agree with our cal...

A novel three-photon probe for the imaging of exogenous Zn(II) ions in live cells with varying emission colors under three-photon excitation is developed. The tuning of the charge transfer state and the emission color of the probe was also demonstrated in the presence of acid.