To achieve population inversion an EDFA uses stimulated emission process where incident photon and emitted photon have same phase. But, alongwith the stimulated emission that creates gain, the gain medium also produces spontaneous emission, which gives rise to the amplified spontaneous emission (ASE) spectrum of the amplifier []. In this paper we have considered the setup to measure amplified s...

The production of single photons using rephased amplified spontaneous emission is examined. This process produces single photons on demand with high efficiency by detecting the spontaneous emission from an atomic ensemble, then applying a population-inverting pulse to rephase the ensemble and produce a photon echo of the spontaneous emission events. The theoretical limits on the efficiency of t...

Bioluminescence imaging is widely used for optical cell tracking approaches. However, reliable and quantitative bioluminescence of transplanted cells in the brain is highly challenging. In this study we established a new bioluminescence imaging protocol dedicated for neuroimaging, which increases sensitivity especially for noninvasive tracking of brain cell grafts. Different D-Luciferin concent...

Small-angle scattering X-ray photon correlation spectroscopy (XPCS) studies were performed using a novel photon-counting pixel array detector with dual counters for each pixel. Each counter can be read out independently from the other to ensure there is no readout dead-time between the neighboring frames. A maximum frame rate of 11.8 kHz was achieved. Results on test samples show good agreement...

We consider monochromatic and isotropic photon emission from circular equatorial Kerr orbiters. derive analytic expressions for the escape probability redshift-dependent total flux collected on celestial sphere as a function of radius black hole parameters. These calculations crucially involve critical curve delineating region that capture in each emitter's sky. This generalizes to finite orbit...

This thesis explores the concept of photon-echo-rephasing of the spontaneous emission from an ensemble of atoms. This generates entangled photon pairs, with intermediate storage and on-demand recall of one photon of the pair. In the first instance, this has applications as a single photon source. A more advanced application is as a building-block of a quantum repeater protocol, which is essenti...

Two-photon-induced fluorescence is observed from the photodynamic phycobiliprotein phycoerythrin. Temporal, spectral, and intensity-dependent properties of the two-photon-induced fluorescence emission from phycoerythrin excited by a 1.06-mum laser beam are reported. The measured two-photon absorption cross section of phycoerythrin is an order of magnitude larger than that of Rhodamine 6G. The p...

The photon emission from a single molecule driven simultaneously by a laser and a slow electric radio frequency (rf) field is studied. We use a non-Hermitian Hamiltonian approach which accounts for the radiative decay of a two-level system modeling the single-molecule source. We apply the renormalization group method for differential equations to obtain long time solution of the corresponding S...