Non-local Quantum Electrodynamics. II. Possibility of correlated 2n-photon absorption in gases leading to VERY High frequency spontaneous emission and Very high order Harmonic Generation

Krishna Rai Dastidar, T. K. Rai Dastidar

arXiv:quant-ph/0204109Apr 19, 20020 citations

Physics of Electronic and Atomic Collisions: ICPEAC X

Two-photon absorption in atomic gases

M. S. Pindzola

Published Jan 1, 1977• 0 citations

OpenAlex

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Non-local Quantum Electrodynamics. II. Possibility of correlated 2n-photon absorption in gases leading to VERY High frequency spontaneous emission and Very high order Harmonic Generation

Krishna Rai Dastidar, T. K. Rai Dastidar

In a recent work [Mod. Phys. Lett A13, p-1265 (1998)] we expounded a non-local Quantum Electrodynamics (QED) which predicted a linear two-photon absorption by an atom placed in a laser field of appropriate intensity and frequency. In this paper we extend our earlier work to show that the theory allows for linear 2n-photon absorption by gaseous matter where, under suitable conditions, n may literally run upto thousands. The consequences of this extension of the theory are outlined and predictions are made which may be verified in laboratories.In a recent work [Mod. Phys. Lett A13, p-1265 (1998)] we expounded a non-local Quantum Electrodynamics (QED) which predicted a linear two-photon absorption by an atom placed in a laser field of appropriate intensity and frequency. In this paper we extend our earlier work to show that the theory allows for linear 2n-photon absorption by gaseous matter where, under suitable conditions, n may literally run upto thousands. The consequences of this extension of the theory are outlined and predictions are made which may be verified in laboratories.

arXiv:quant-ph/0204109Apr 19, 20020 citations

{(\mathrm{photon}\mathrm{flux})}^{8}

and should be observable using available techniques. Good agreement is obtained with Zernik's exact calculation of the two-photon ionization rate of metastable

2S

hydrogen. Approximate calculations are made for the rare gases. Assuming "typical" experimental conditions of a gas density of \ensuremath{\sim}

{10}^{20}

atoms ${\mathrm{cm}}^{\ensuremath{-}3}$ and a ruby laser focused into a volume of \ensuremath{\sim}${10}^{\ensuremath{-}8}$

{\mathrm{cm}}^{3}

, we find that the flux required to liberate one electron during a 10-nsec pulse is \ensuremath{\sim}

{10}^{29}

${\mathrm{cm}}^{\ensuremath{-}2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ for Xe, Kr, and Ar and \ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}

{10}^{30}

photons ${\mathrm{cm}}^{\ensuremath{-}2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ for Ne and He. These gases ionize with the simultaneous absorption of 7, 8, 9, 13, and 14 photons, respectively. The predicted rate for Xe is found to be in excellent agreement with the recent direct measurements of Voronov and Delone. We conclude that multiphoton ionization provides the initial electrons required for the optical breakdown of gases, though it does not account for the over-all growth of the discharge except possibly at very low pressures. Impurity atoms (particularly heavy rare gases) may be the source of "initiating" electrons in Ne and He.