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

arXiv:1407.1589 · Laser Physics

High and uniform coherence creation in Doppler-broadened double Λ-like atomic system by a train of femtosecond optical pulses

Amarendra K Sarma, Pawan Kumar

Published Apr 1, 2015• 0 citations
arXivHTMLPDF

Abstract

We present a detailed analysis of coherence creation in a four-level double Λ-like atomic system using a train of ultra-short few-cycle Gaussian pulses. The effect of the Doppler broadening has been analyzed. It is possible to create high coherence across all the velocity groups in the atomic ensemble using pulses with low repetition frequency. The accumulation of coherence at different radial locations within the atomic beam cross-section as a function of the number of pulses in the train is also reported. We find that pulse trains with lower repetition frequencies are able to generate high and nearly uniform coherence in a substantial part of the atomic system.

DOI
10.1088/1054-660x/25/5/056001

Related papers

Coherent manipulation of four-level double lambda-like atomic system by a train of ultra-short few-cycle-optical pulses

Pawan Kumar, Amarendra K. Sarma

We have demonstrated that near complete coherence can be achieved in a four level double lambda-like systems using a train of ultra-short optical pulses. The effect of the Doppler broadening has been analyzed and a scheme has been proposed for establishing high and uniform coherence across different velocity groups in the atomic ensemble. We have also presented a novel scheme of excitation using chirped pulses and shown that in addition to generating coherence in the system it is possible to alter the translational states of the atoms.

arXiv:1401.3417•Jan 15, 2014•1 citation

Accumulative effects in the coherence of three-level atoms excited by femtosecond-laser frequency combs

D. Felinto, L. H. Acioli, S. S. Vianna

We investigate coherent accumulation processes in three-level atoms excited by a train of ultrashort pulses in the case where the atomic relaxation times are greater than the laser repetition period. In this situation the resonances of the laser field with the atomic system are determined by the laser frequency comb rather than by the spectrum of a single pulse. Using the density matrix formalism, we develop a perturbative theory that is valid for arbitrary pulse shapes. The excitation of a Doppler-broadened atomic vapor by hyperbolic-secant pulses and $0\ensuremath{\pi}$ pulses is analyzed. It is shown that pulse shape has a great influence on the accumulation process and can change the spectral periodicity of the pattern impressed on the Doppler profile of the medium due to the two-photon absorption process. The effect of interpulse phases is also investigated, and we show that the atomic populations can vary by more than one order of magnitude with small variations of the laser repetition rate, while being insensitive to variations of the laser offset. Finally, the theory is adapted for the temporal-coherent-control technique, and its results are compared with previously reported experimental data.

Physical Review A•Oct 12, 2004•62 citations

Simultaneous control of optical dipole force and coherence creation by super-Gaussian femtosecond pulses in Λ -like atomic systems

Pawan Kumar, Parvendra Kumar, Amarendra K. Sarma

We report a study of the optical dipole force on a beam of neutral three-level, $\ensuremath{\Lambda}$-like atomic system induced by a femtosecond super-Gaussian pulse. We show that maximum coherence between the ground state $|1\ensuremath{\rangle}$ and the excited state $|2\ensuremath{\rangle}$ could be achieved using a train of femtosecond pulses. In addition, it is possible to control the trajectory of the atoms in an atomic beam by using the same scheme. The robustness of the scheme against the variation of the pulse parameters is also investigated.

arXiv:1310.8142•Physical Review A•Mar 19, 2014•12 citations

Coherent Population Trapping of a Three-level Atom Interacting with Few Cycle Pulse Train

蔡勋明 CAI Xun-minga, 范梦慧 FAN Meng-huib

The poulation transfer and coherent population trapping of a three-level atom interacting with few cycle pulse train are studied.The density matrix equation in interation picture is numerical solved without rotating wave approximation.The research indicates that if a three-level atom interacts with a few cycle pulse train,the population transfer of level and the coherence of ground state will be gradual accumulated.When the repetition frequency of pulses is integer points of the ground-state splitting,the three atom interacts with pulse train can be seen as the atom interacts with two tenoning frequency of the frequency comb.So the system will be in the dark state and reach coherent population trapping.If the parameters of few-cycle pulse are appropriately selected,the coherence of three-level system will evolute into stable value in 0.5 nanosecond.The coherent population trapping in the three-level is generated.Comparing with the pulse that the pulse width is 100 femtoseconds,the build-up time of coherent population trapping by few cycle pulse train is shortened two orders of magnitude.When the ground-state splitting is wided enough and the carrier frequency of pulse is ω=(ω1+ω2)/2,where,are the atomic transition frequency,the doppler frequency shift that is aroused by the movement of atom won't destroy the coherent population trapping of atom.The reason is that all tenoning frequencies of the frequency comb have the same frequency shift,so the condition of coherent population trapping is still meeted.

ACTA PHOTONICA SINICA•Jan 1, 2013•0 citations

Coherence induced by a train of ultrashort pulses in a Λ-type system

Marco Polo Moreno de Souza, S. S. Vianna

We present an analysis of coherent population trapping in a three-level Λ system when excited by an ultrashort pulse train near the one- and two-photon resonances. Numerical results using Bloch equations give the transient response of the system and clearly reveal a comb of electromagnetically induced transparency (EIT) lines. An analytical solution to describe the EIT lines is derived in the steady-state regime and in the weak field limit. Moreover, numerical results indicate that selective velocity spectroscopy makes possible the observation of the comb of EIT lines in Doppler broadening media.

Journal of the Optical Society of America B•Apr 14, 2011•16 citations

High-resolution coherence spectroscopy using pulse trains

J. Mlynek, Wulfhard K. Lange, H. Harde +1 more

An infinite train of short light pulses is used for periodic creation of a coherent superposition of atomic substates. The coherence is sensitively detected by an optical probe beam using a polarization-selective technique. Narrow resonances are observed whenever the pulse repetition rate or its multiples coincide with an atomic Bohr frequency. Half-widths (full width at half maximum) of 20 kHz have been obtained for the Zeeman splitting of the sodium ground state.

Physical Review A•Aug 1, 1981•59 citations
We present a detailed analysis of coherence creation in a four-level double Λ-like atomic system using a train of ultra-short few-cycle Gaussian pulses. The effect of the Doppler broadening has been analyzed. It is possible to create high coherence across all the velocity groups in the atomic ensemble using pulses with low repetition frequency. The accumulation of coherence at different radial locations within the atomic beam cross-section as a function of the number of pulses in the train is also reported. We find that pulse trains with lower repetition frequencies are able to generate high and nearly uniform coherence in a substantial part of the atomic system.
We have demonstrated that near complete coherence can be achieved in a four level double lambda-like systems using a train of ultra-short optical pulses. The effect of the Doppler broadening has been analyzed and a scheme has been proposed for establishing high and uniform coherence across different velocity groups in the atomic ensemble. We have also presented a novel scheme of excitation using chirped pulses and shown that in addition to generating coherence in the system it is possible to alter the translational states of the atoms.
We investigate coherent accumulation processes in three-level atoms excited by a train of ultrashort pulses in the case where the atomic relaxation times are greater than the laser repetition period. In this situation the resonances of the laser field with the atomic system are determined by the laser frequency comb rather than by the spectrum of a single pulse. Using the density matrix formalism, we develop a perturbative theory that is valid for arbitrary pulse shapes. The excitation of a Doppler-broadened atomic vapor by hyperbolic-secant pulses and $0\ensuremath{\pi}$ pulses is analyzed. It is shown that pulse shape has a great influence on the accumulation process and can change the spectral periodicity of the pattern impressed on the Doppler profile of the medium due to the two-photon absorption process. The effect of interpulse phases is also investigated, and we show that the atomic populations can vary by more than one order of magnitude with small variations of the laser repetition rate, while being insensitive to variations of the laser offset. Finally, the theory is adapted for the temporal-coherent-control technique, and its results are compared with previously reported experimental data.
We report a study of the optical dipole force on a beam of neutral three-level, $\ensuremath{\Lambda}$-like atomic system induced by a femtosecond super-Gaussian pulse. We show that maximum coherence between the ground state $|1\ensuremath{\rangle}$ and the excited state $|2\ensuremath{\rangle}$ could be achieved using a train of femtosecond pulses. In addition, it is possible to control the trajectory of the atoms in an atomic beam by using the same scheme. The robustness of the scheme against the variation of the pulse parameters is also investigated.
The poulation transfer and coherent population trapping of a three-level atom interacting with few cycle pulse train are studied.The density matrix equation in interation picture is numerical solved without rotating wave approximation.The research indicates that if a three-level atom interacts with a few cycle pulse train,the population transfer of level and the coherence of ground state will be gradual accumulated.When the repetition frequency of pulses is integer points of the ground-state splitting,the three atom interacts with pulse train can be seen as the atom interacts with two tenoning frequency of the frequency comb.So the system will be in the dark state and reach coherent population trapping.If the parameters of few-cycle pulse are appropriately selected,the coherence of three-level system will evolute into stable value in 0.5 nanosecond.The coherent population trapping in the three-level is generated.Comparing with the pulse that the pulse width is 100 femtoseconds,the build-up time of coherent population trapping by few cycle pulse train is shortened two orders of magnitude.When the ground-state splitting is wided enough and the carrier frequency of pulse is ω=(ω1+ω2)/2,where,are the atomic transition frequency,the doppler frequency shift that is aroused by the movement of atom won't destroy the coherent population trapping of atom.The reason is that all tenoning frequencies of the frequency comb have the same frequency shift,so the condition of coherent population trapping is still meeted.
We present an analysis of coherent population trapping in a three-level Λ system when excited by an ultrashort pulse train near the one- and two-photon resonances. Numerical results using Bloch equations give the transient response of the system and clearly reveal a comb of electromagnetically induced transparency (EIT) lines. An analytical solution to describe the EIT lines is derived in the steady-state regime and in the weak field limit. Moreover, numerical results indicate that selective velocity spectroscopy makes possible the observation of the comb of EIT lines in Doppler broadening media.