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.

We demonstrate a method to improve the measurement sensitivity of two-photon frequency-domain lifetime measurements in poor signal to background conditions. This technique uses sinusoidal modulation of the two-photon excitation source and detection of the second harmonic of the modulation frequency that appears in the emission. Additionally, we present the mathematical model which describes how...

We show that broad-area cascade lasers with no absorbing intracavity elements support the spontaneous formation of two-dimensional bright localized structures in a dark background. These cavity solitons consist of islands of two-photon emission embedded in a background of single-photon emission. We discuss the mechanisms through which these structures are formed and interact, along with their p...

Single-photon stimulated radiative interactions are universally symmetric relative to emission and absorption. We point out that certain multiphoton stimulated processes, whose completion is dependent on the spontaneous emission of at least one photon, do not behave analogously. The broken symmetry found in such cases invalidates simple correlations between population inversion and laser gain. ...

We present the MR and single-photon emission CT findings in a 3-year-old patient in whom Klüver-Bucy syndrome developed after Reye syndrome. MR images showed diffuse brain atrophy, which was predominant in the temporal lobes, and single-photon emission CT scans showed decreased cerebral perfusion in the bilateral temporal lobes and associated cortical areas.

Controlling the ouput of a light emitter is one of the basic tasks of photonics, with landmarks such as the laser and single-photon sources. The development of quantum applications makes it increasingly important to diversify the available quantum sources. Here, we propose a cavity QED scheme to realize emitters that release their energy in groups, or "bundles" of N photons, for integer N. Clos...

High-bit-rate nanocavity-based single photon sources in the 1,550-nm telecom band are challenges facing the development of fibre-based long-haul quantum communication networks. Here we report a very fast single photon source in the 1,550-nm telecom band, which is achieved by a large Purcell enhancement that results from the coupling of a single InAs quantum dot and an InP photonic crystal nanoc...

Two-photon emission is a process in which electron transition between quantum levels occurs through the simultaneous emission of two photons. This phenomenon is important for astrophysics and atomic physics, and semiconductor twophoton emission was recently proposed as a compact source of entangled photons, essential for practical quantum information processing, and three orders of magnitude mo...

The electron pair emission from a W(001) surface was studied using a coincidence time-of-flight spectrometer. The aim of this study was to compare the pair emission upon electron impact and upon photon absorption. The energy distributions are markedly different for these two experiments. From this we conclude that the photon-stimulated pair emission carries a significant contribution from a dou...