arXiv subjects

Amiram Ron

Publications and source records attributed to Amiram Ron.

6 recordsLinked to original sources

arXiv2014

Diffraction manipulation by four-wave mixing

We suggest a scheme to manipulate paraxial diffraction by utilizing the dependency of a four-wave mixing process on the relative angle between the light fields. A microscopic model for four-wave mixing in a Lambda-type level structure is introduced and compared to recent experimental data. We show that images with feature size as low as 10 micrometers can propagate with very little or even negative diffraction. The mechanism is completely different from that conserving the shape of spatial solitons in nonlinear media, as here diffraction is suppressed for arbitrary spatial profiles. At the same time, the gain inherent to the nonlinear process prevents loss and allows for operating at high optical depths. Our scheme does not rely on atomic motion and is thus applicable to both gaseous and solid media.

physics.optics↗

arXiv2012

Coherent Diffusion of Polaritons in Atomic Media

Coherent diffusion pertains to the motion of atomic dipoles experiencing frequent collisions in vapor while maintaining their coherence. Recent theoretical and experimental studies on the effect of coherent diffusion on key Raman processes, namely Raman spectroscopy, slow polariton propagation, and stored light, are reviewed in this Colloquium.

quant-ph↗

arXiv2007

Slowing the Decay of an Excited Atom by the Presence of a Detector

The decay of an excited is shown to slow down in the presence of a photo detector. This is similar to the behavior of an atom in a mistuned cavity, and under the conditions of the quantum Zeno effect. No external perturbing field is applied to measure the survival probability of the unstable state.

quant-ph↗

arXiv2005

Titanium plasma source for capillary discharge extreme ultraviolet lasers

A technique to generate jets of pure Titanium plasma is presented. A Ti wire is exploded in an Alumina capillary sealed with 1atm. of air inside. The generated plasma emerges from the capillary (to a high-vacuum environment) by ripping a thin Ti foil that seals one of the capillary ends. The generated plasma jets have a velocity of up to $4.5\pm0.5mm/μs$, an electron temperature of $1.5\pm0.5eV$ and a ion density of $2.7\pm1\times10^{17}/cc$. The plasma source was designed for a capillary discharge extreme ultraviolet laser experiment, but might also be useful to other application such as a target for Z-pinch experiments.

physics.plasm-ph↗

arXiv2000

Decoherence of a Pointer by a Gas Reservoir

We study the effect of the environment on the process of the measurement of a state of a microscopic spin half system. The measuring apparatus is a heavy particle, whose center of mass coordinates can be considered at the end of the measurement as approximately classical, and thus can be used as a pointer. The state of the pointer, which is the result of its interaction with the spin, is transformed into a mixed state by the coupling of the pointer to the environment. The environment is considered to be a gas reservoir, whose particles interact with the pointer. This results in a Fokker-Planck equation for the reduced density matrix of the pointer. The solution of the equation shows that the quantum coherences, which are characteristic to the entangled state between the probabilities to find the pointer in one of two positions, decays exponentially fast in time. We calculate the exponential decay function of this decoherence effect, and express it in terms of the parameters of the model.

quant-ph↗

arXiv1999

The Effect of Neutral Atoms on Capillary Discharge Z-pinch

We study the effect of neutral atoms on the dynamics of a capillary discharge Z-pinch, in a regime for which a large soft-x-ray amplification has been demonstrated. We extended the commonly used one-fluid magneto-hydrodynamics (MHD) model by separating out the neutral atoms as a second fluid. Numerical calculations using this extended model yield new predictions for the dynamics of the pinch collapse, and better agreement with known measured data.

physics.plasm-ph↗