arXiv:1204.3526

Propagation of light in low pressure gas

Jacques Moret‐Bailly

Published Apr 13, 2012• 0 citations

Abstract

The criticism by W. E. Lamb, W. Schleich, M. Scully, C. Townes of a simplified quantum electrodynamics which represents the photon as a true particle is illustrated. Collisions being absent in low-pressure gas, exchanges of energy are radiative and coherent. Thin shells of plasma containing atoms in a model introduced by Strömgren are superradiant, seen as circles possibly dotted. Spectral radiance of novae has magnitude of laser radiance, and column densities are large in nebulae: Superradiance, multiphoton effects, etc., work in astrophysics. The superradiant beams induce multiphotonic scatterings of light emitted by the stars, brightening the limbs of plasma bubbles and darkening the stars. In excited atomic hydrogen, impulsive Raman scatterings shift frequencies of light. Microwaves exchanged with the Pioneer probes are blueshifted, simulating anomalous accelerations. Substituting coherence for wrong calculations in astrophysical papers, improves results, avoids "new physics".

DOI: 10.48550/arxiv.1204.3526

Related papers

Optical coherence in interstellar space simplifies universe model

Jacques Moret‐Bailly

Expansion of stellar winds made essentially of protons and electrons , cools them in a spherical shell around Strömgren's sphere, into excited H atoms by which superradiance and associated super-absorption transform energy received from star into emissions by sphere limb. In interstellar space, stimulated Raman losses redshift stellar light by fine structure excitations of H in 2P states.

May 18, 20190 citations

Introduction of coherence in astrophysical spectroscopy

Jacques Moret‐Bailly

By confusing the radiance of a single mode light beam, constant in a transparent medium, with the irradiance which decreases away from the source, Menzel purports to show that coherent interactions of light with the diluted media of astrophysics, are negligible. Therefore, to study the interaction of light with gases, astrophysicists use Monte Carlo computations which work to study nuclear systems, but not optics: optical modes which may be defined in inhomogeneous media or for the emissions of single atoms interact coherently with these systems: a unique formula represents, according to the sign of a parameter, absorption and coherent emission. The optical and spectroscopic properties of a very simple model, an extremely hot source in an isotropic cloud of pure, low pressure, initially cold, huge hydrogen cloud are studied using Planck's and Einstein's theories. The similarities of the images and the spectra of this simple model with astronomical observations, for instance of SNR1987A, Einstein cross, lyman break galaxies, quasars,... is so large that this model may be an elementary first step in the study of many astrophysical objects. Adaptations of the model to complex astrophysical systems could represent them using only the old, standard theories of physics commonly used in laser spectroscopy.

arXiv:1002.1630Feb 8, 20100 citations

Coherent Raman scattering in a low pressure gas

Jacques Moret‐Bailly

Incoherent emissions of light by a gas require collisions of molecules, while coherent emissions, at low pressure, are amplifications of pre-existing rays. At very low pressure, very accidental collisions of atoms of an excited gas initiate flare-ups, and Raman pumping of the gas by a temporally incoherent ray of light absorbs molecular quanta without other energy diffusion.

Jan 26, 20200 citations

White light through low pressure H atoms.

Jacques Moret‐Bailly

Propagation of white light in very low pressure, relatively cold H atoms of space, is spatially coherent. Lyman alpha absorption pumps atoms to 2P states. Stimulated Raman losses (SRL) using fine levels quanta of excited H, redshift light at all frequencies until an alpha superradiant flare de-excites H and super-absorbs a black line of a Lyman forest. Pumping stops when an absorbed line is shifted to alpha frequency, so that beta and gamma lines are visibly absorbed. If there is energy enough at Lyman beta frequency, a similar, slow redshift restarts the process. A quasar H spectrum is generated. Hubble redshift evaluates a column density of H in 2P state.

Jul 15, 20190 citations

Coherent interactions of low pressure atomic hydrogen with light emitted by an extremely hot black source.

Jacques Moret‐Bailly

For a long time, coherent interactions of light with gas wereconsidered as negligible [1]. After discovery of lasers, manyapplications were found [2], thought it remains discussions [3].Here, we study propagation of light emitted by the simplestsource (a very hot blackbody), and propagating in the simplestmedium (collisionless atomic hydrogen), because it seems thatthis work was never done. For this, we use only well known,theoretically and experimentally studied laws of physics.

Aug 1, 20170 citations

Quantum Coherence and Superradiant Emission: From Lasing Without Inversion to Sky Laser and the QASER

Luqi Yuan

This work is focused on quantum coherence and superradiant emission in a dense pencil-like multi-level medium where many novel effects appear such as transient lasing without inversion, coherence-brightened sky laser, and quantum amplification by superradiant emission of radiation. \n\nWe start from an interesting cascade model where quantum coherence effects can lead to surprising phenomena, gain without population inversion and gain suppression, under different parameters. We further show superradiant emission inside helium plasma. The population evolution shows the decay is significantly faster than collisional decoherence and spontaneous decay rates. This indicates superradiant coherent behavior of the atomic system inside the plasma.\n\nBased on these results, we demonstrate lasing without inversion on a time scale shorter than the decoherence time. The possibility of transient lasing without inversion holds promise for lasing in the extreme-ultraviolet/x-ray regime. We propose experiments to demonstrate this in helium or helium-like ions plasma. \n\nWe also study coherent emission from ambient air and demonstrate efficient generation of laser-like beams directed both forward and backward with respect to a nanosecond ultraviolet pumping laser beam. The emission process exhibits nonadiabatic quantum coherence, which is similar in nature to Dicke superradiance. This coherence-brightened backward light source in air provides possibility for atmospheric remote sensing through a phase-matched coherent Raman scattering process.\n\nFinally, we present a new kind of quantum amplifier, the QASER (quantum amplification by superradiant emission of radiation), based on collective superradiant emission which does not require initial population in the excited state. We show that parametric resonance between the driving field and collective superradiant oscillations of the atomic polarization can yield light amplification at high frequencies. The resulting superradiant amplifier is many orders of magnitude more efficient than nonlinear multiphoton excitation and holds promise as a new way to generate high-frequency coherent radiation.

Sep 30, 20140 citations