Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Conference on Lasers and Electro-Optics

Bichromatic coherent excitation: application to the excitation of mesospheric sodium

Xin Miao Zhao, Jean‐Claude Diels

Published May 21, 1995• 0 citations
OpenAlex

Abstract

A new scheme for coherently pumping two-photon transitions is demonstrated theoretically-It is shown that a total inversion can be achieved by using a pair of bichromatic ultrashort pulses tuned close to an intermediate resonance. The proximity of the intermediate resonance greatly enhances the efficiency of the process, making it possible to reach total inversion with energy densities of the order of microjoules per square centimeter. At the same time, the resonance conditions are controlled in such a way that at no time a dipole moment is created (the off-diagonal elements corresponding to dipole transitions remain <0.1).

Related papers

Coherent pumping of mesospheric sodium to create a bichromatic guidestar

Jens Biegert, J.-C. Diels, Peter W. Milonni

Summary form only given. We exploit coherent interaction properties to efficiently pump sodium from the 3s/sub 1/2/ ground state to the 4s/sub 1/2/ upper state via the 3p/sub 3/2/ state. Even though the excitation is nonlinear, the required intensities are reduced to levels required to resonantly pump single photon transitions in sodium, because of the particular choice of laser frequencies which are near resonance with the intermediate levels. Furthermore, the intermediate state is left unpopulated after the excitation sequence. A computer simulation solves the nonlinear Schrodinger equation for this system, comprised of 32 hyperfine levels connected by 112 possible transitions. The levels are summed over the velocity distribution for mesospheric sodium to account for Doppler broadening which is the dominant dephasing process.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jan 1, 2000•0 citations

Feasibility Study of a Bichromatic Guidestar - Coherent 2-Photon Bichromatic Excitation of Mesospheric Sodium

Jens Biegert, Jean‐Claude Diels

Theoretical results from a full hyperfine structure density matrix computation indicate that a bichromatic sodium guidestar based on two-photon bichromatic coherent excitation should require laser powers only on the order of 10 W.

Nonlinear Optics•Jan 1, 2000•0 citations

Feasibility study of a bichromatic guidestar-coherent 2-photon bichromatic excitation of mesospheric sodium

Jens Biegert, J.-C. Diels

Theoretical results from a full hyperfine structure density matrix computation indicate that a bichromatic sodium guidestar based on two-photon bichromatic coherent excitation should require laser powers only on the order of 10 W.

Nonlinear Optics: Materials, Fundamentals, and Applications. Technical Digest. Postconference Edition. TOPS Vol.46 (IEEE Cat. No.00CH37174)•Nov 8, 2002•0 citations

Feasibility study to create a polychromatic guidestar in atomic sodium

Jens Biegert, Jean‐Claude Diels

We have theoretically determined and experimentally confirmed that polychromatic multiphoton coherent excitation can be used to most efficiently achieve a selective total population inversion in a multilevel system. These results suggest a solution to the problem of using mesospheric sodium as a guidestar.

Physical Review A•Apr 7, 2003•13 citations

Optimal Bichromatic Two-Photon Excitation with Near-Resonant Chirped Pulses

Carles Serrat, Jens Biegert, Theodore E. Simos +1 more

We investigate a method for creating complete population inversion in a three level system by using bichromatic two‐photon coherent excitations with laser pulses, and study the dependence of the optimal population transfer on the chirp of the pulses. We observe that the population inversion does not monotonously decrease with increasing the time‐bandwidth product, and that the excitation depends on the sign of the chirp of the individual pulses. Our results, which evidence a worthwhile strategy for coherent population transfer in three level systems, are particularized to the level structure of atomic sodium, with regard to applications in bichromatic mesospheric guide stars.

AIP conference proceedings•Jan 1, 2007•1 citation

Coherent control of resonant two-photon transitions by counterpropagating ultrashort pulse pairs

Woojun Lee, Hyosub Kim, Kyungtae Kim +1 more

We describe optimized coherent control methods for two-photon transitions in atoms of a ladder-type three-state energy configuration. Our approach is based on the spatial coherent control scheme, which uses counterpropagating ultrashort laser pulses to produce complex excitation patterns in an extended space. Because coherent control requires constructive interference of constituent transition pathways, applying it to an atomic transition with a specific energy configuration requires specially designed laser pulses. We show in an experimental demonstration that two-photon transition with an intermediate resonant energy state can be coherently controlled and retrieved from the resonance-induced background, when phase flipping of the laser spectrum near the resonant intermediate transition is used. A simple reason for this behavior is the fact that the transition amplitude function (added to give an overall two-photon transition) changes its sign at the intermediate resonant frequency and, thus, by proper spectral-phase programing, the excitation patterns (or the position-dependent interference of the transition given as a consequence of the spatial coherent control) can be well isolated in space along the focal region of the counterpropagating pulses.

arXiv:1503.02378•Physical Review A•Sep 14, 2015•6 citations
A new scheme for coherently pumping two-photon transitions is demonstrated theoretically-It is shown that a total inversion can be achieved by using a pair of bichromatic ultrashort pulses tuned close to an intermediate resonance. The proximity of the intermediate resonance greatly enhances the efficiency of the process, making it possible to reach total inversion with energy densities of the order of microjoules per square centimeter. At the same time, the resonance conditions are controlled in such a way that at no time a dipole moment is created (the off-diagonal elements corresponding to dipole transitions remain <0.1).
Summary form only given. We exploit coherent interaction properties to efficiently pump sodium from the 3s/sub 1/2/ ground state to the 4s/sub 1/2/ upper state via the 3p/sub 3/2/ state. Even though the excitation is nonlinear, the required intensities are reduced to levels required to resonantly pump single photon transitions in sodium, because of the particular choice of laser frequencies which are near resonance with the intermediate levels. Furthermore, the intermediate state is left unpopulated after the excitation sequence. A computer simulation solves the nonlinear Schrodinger equation for this system, comprised of 32 hyperfine levels connected by 112 possible transitions. The levels are summed over the velocity distribution for mesospheric sodium to account for Doppler broadening which is the dominant dephasing process.
We investigate a method for creating complete population inversion in a three level system by using bichromatic two‐photon coherent excitations with laser pulses, and study the dependence of the optimal population transfer on the chirp of the pulses. We observe that the population inversion does not monotonously decrease with increasing the time‐bandwidth product, and that the excitation depends on the sign of the chirp of the individual pulses. Our results, which evidence a worthwhile strategy for coherent population transfer in three level systems, are particularized to the level structure of atomic sodium, with regard to applications in bichromatic mesospheric guide stars.
We describe optimized coherent control methods for two-photon transitions in atoms of a ladder-type three-state energy configuration. Our approach is based on the spatial coherent control scheme, which uses counterpropagating ultrashort laser pulses to produce complex excitation patterns in an extended space. Because coherent control requires constructive interference of constituent transition pathways, applying it to an atomic transition with a specific energy configuration requires specially designed laser pulses. We show in an experimental demonstration that two-photon transition with an intermediate resonant energy state can be coherently controlled and retrieved from the resonance-induced background, when phase flipping of the laser spectrum near the resonant intermediate transition is used. A simple reason for this behavior is the fact that the transition amplitude function (added to give an overall two-photon transition) changes its sign at the intermediate resonant frequency and, thus, by proper spectral-phase programing, the excitation patterns (or the position-dependent interference of the transition given as a consequence of the spatial coherent control) can be well isolated in space along the focal region of the counterpropagating pulses.