We show that the reduction in photon number fluctuations at laser threshold often cited as a fundamental laser property does not occur in small semiconductor lasers. The conventional theory of threshold noise is not valid in lasers with a spontaneous emission factor larger than 10. If the spontaneous emission factor is larger than 10, the photon number statistics even remain thermal far above t...

Supercritical accretion flows inevitably produce radiation-pressure driven outflows, which will Compton up-scatter soft photons from the underlying accretion flow, thereby making hard emission. We perform two dimensional radiation hydrodynamic simulations of supercritical accretion flows and outflows, incorporating such Compton scattering effects, and demonstrate that there appears a new hard s...

In this report we explore the structural and optical properties of GaAs/AlGaAs heterostructure nanowires grown by metalorganic vapour phase epitaxy using gold seed-particles. The optical studies were done by low-temperature cathodoluminescence (CL) in a scanning electron microscope (SEM).We perform a systematic investigation of how thenanowire growth-temperature affects the total photon emissio...

Semiconductor cascade lasers have larger photon noise than conventional semiconductor lasers as a result of positive correlations in photon emission in different gain stages which are connected electrically in series. The photon noise of a cascade laser can be related to the photon noise of a single-stage laser with a scaled external circuit impedance. This scaling relation for the photon noise...

A theoretical formalism is presented to investigate enhanced radiative decay of excited dipoles in photonic crystal waveguides and nanocavities with a view to achieving efficient single-photon emission from embedded quantum dots. Surprisingly, large enhancement effects are achievable in both waveguides and nanocavities, and enhanced emission in the waveguide is shown to scale proportionally (in...

The one- and two-photon excitation emission properties of water soluble glutathione monolayer protected gold clusters were investigated. Strong two-photon emission was observed from the gold clusters. The two-photon absorption cross section of these gold clusters in water was deduced from the z-scan measurement to be 189 740 GM, which is much higher compared to organic fluorescent dyes and quan...

bhw = line half-width, Å E = radiative energy, W Eabs = radiative energy absorbed by cell, W Ebundle = radiative energy carried by photon bundle, W Eemis = emission energy, W Etrans = transmitted radiative energy, W Kn;1 = freestream Knudsen number, dimensionless k, k1, k2 = line-center index, dimensionless L = nose radius of the Stardust blunt body, m l1;2 = ratio between face endpoints, m Nra...

We show that the AC-Stark shift (light-shift) is a powerful and versatile tool to control the emission of a photon-echo in the context of optical storage. As a proof-of-principle, we demonstrate that the photon-echo efficiency can be fully modulated by applying light-shift control pulses in an erbium-doped solid. The control of the echo emission is attributed to the spatial gradient induced by ...