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

Physical Review Letters

Coherent Transient Enhancement of Optically Induced Resonant Transitions

Nirit Dudovich, Dan Oron, Yaron R. Silberberg

Published Mar 7, 2002• 102 citations
Publisher

Abstract

By applying pulse shaping techniques to a broadband 100 fs pulse in resonance with a two-level atomic transition, we are able to enhance the peak transient excited level population relative to that achievable with transform limited pulses. We also demonstrate how the dispersion induced by the absorption line itself leads to similar rapidly oscillating transients in the excited population. These transient population effects are applicable in any multiphoton resonant transition.

DOI
10.1103/physrevlett.88.123004

Related papers

Optical multiple pulse sequences for multiphoton selective excitation and enhancement of forbidden transitions

W. S. Warren, Ahmed H. Zewail

In this paper we present novel and simple pulse sequences for enhancing the intensity of forbidden or highly nonresonant optical transitions. These sequences provide a straightforward approach to circumventing the most serious limitation of optical coherent transient spectroscopy: Available laser intensities are often insufficient to excite a significant fraction of the ground state population into desired excited states, either because of large inhomogeneous broadening or, in the case of multiphoton absorption, large anharmonicities. Optical phase modulation (which can be produced by an acousto-optic modulator) or amplitude modulation (which can be produced by an interferometer) with carefully chosen pulse flip angles and delays can effectively remove even very large energy mismatches, thus permitting essentially complete population inversions arbitrarily far from resonance. Coherent averaging theory and computer calculations are used to derive particularly valuable sequences. Pumping enhancement of 103–105 (depending on individual molecular parameters) for these modulated pulse sequences are predicted. Specific applications to multiphoton pumping of local vibrational modes are discussed.

The Journal of Chemical Physics•Mar 15, 1983•44 citations

Coherent quantum control of multiphoton transitions by shaped ultrashort optical pulses

Doron Meshulach, Yaron R. Silberberg

Multiphoton transitions can be reached by many routes through a continuum of virtual levels. We show that the transition probability of two-photon and multiphoton processes can be controlled by tailoring the shape of an ultrashort excitation pulse, so that the many paths leading to the final state interfere to give a desired probability amplitude. We analyze the effect of pulse shapes on N-photon absorption as well as on Raman transitions. We show theoretically that certain tailored dark pulses do not excite the system at all, while other shaped pulses induce transitions as effectively as transform limited pulses, even when their peak amplitudes are greatly reduced. These results are confirmed experimentally for two-photon transitions in atomic cesium.

Physical Review A•Aug 1, 1999•366 citations

Control of excited-state population and vibrational coherence with shaped-resonant and near-resonant excitation

Tiago Buckup, Jürgen Hauer, Carles Serrat +1 more

We investigated numerically and experimentally the enhancement of vibrational coherence and population transfer in solution using tailored pulses. The general control mechanism is based on the precise control of the absorption after excitation with multipulses. Transient absorption was used as an experimental method to quantify the enhancement after the excitation with a shaped pump pulse in the low-pulse energy regime. A density-matrix approach was used to investigate the effect of the shaped excitation of a four-level system (two ground-state vibrational levels + two excited-state vibrational levels). Density-matrix simulation results suggest similar wavelength dependence as observed in the transient absorption experiment. The results show that enhancement of population transfer and vibrational coherence depends crucially on the overlap between the excitation pulse spectrum and the molecular absorption band.

Journal of Physics B Atomic Molecular and Optical Physics•Mar 26, 2008•34 citations

Observation and Symmetry-Based Coherent Control of Transient Two-Photon Absorption: The Bright Side of Dark Pulses

Andrey Gandman, Leonid Rybak, Zohar Amitay

We present and experimentally demonstrate for the first time the observation and femtosecond coherent control over the temporal evolution of a transient population that is excited via nonresonant two-photon absorption. Based on symmetry properties of the two-photon absorption process, the exciting femtosecond pulses are phase-shaped to photoinduce different evolutions of the transient excited population for a given final excited population. As a study case, we focus here on the attractive case of two-photon dark pulses that, although inducing zero final population (hence, the terminology of "dark pulses"), they induce a transient excited population during the pulse irradiation that can significantly deviate from zero. This nonzero transient population can be viewed as the bright side of such dark pulses. The symmetry-based coherent control is demonstrated first with dark pulses that we shape to induce transient excited population that at all times is kept below different target levels. Then, it is further demonstrated with pairs of dark pulses where one is rationally shaped to induce temporal evolution of the transient excited population that is the inverse of the evolution induced by the other. The work is conducted in the weak-field regime with the sodium atom as the model system. The approach developed here is general, conceptually simple, and very effective.

Physical Review Letters•Jul 23, 2014•6 citations

Coherent control and quantum shaping with the laser pulse

Li Yongfang

The interaction between the laser pulse with a small-area and a three-level atomic system is investigated.The formation and characterization of the shaped laser pulse are analyzed and the two-photon transition is studied with the shaped laser pulse.The influence of the relaxation of the excited state and the length of the shaping medium on the two-photon absorption is discussed.Based on the dispersion theory the oscillation of the transient twophoton transition is explained.The result indicates that the transition probability of two-photon absorption evolves regularly with the several values of parameters such as the length of medium(l),relaxation time(t2) and bandwidth(Δω).Meanwhile the transition probability appears in the transient oscillation.

Journal of Shaanxi Normal University•Jan 1, 2011•0 citations

Coherent control of two-photon transitions in a two-level system with broadband absorption

Shian Zhang, Hui Zhang, Tianqing Jia +2 more

Multiphoton transition probability can be manipulated by tailoring the ultrashort laser pulses. In this paper, we theoretically and experimentally investigate the influence of the absorption bandwidth and line shape on the coherent control of two-photon transitions in two-level system by manipulating the femtosecond laser pulse with the $\ensuremath{\pi}$ spectral phase step. A coherent feature with a coherent peak and two coherent dips can be achieved if the absorption bandwidth is less than twice of the laser spectral bandwidth. The absorption bandwidth decides the coherent peak or dip intensity, and the absorption line shape affects the symmetry of the two coherent dips.

Physical Review A•Oct 2, 2009•16 citations
By applying pulse shaping techniques to a broadband 100 fs pulse in resonance with a two-level atomic transition, we are able to enhance the peak transient excited level population relative to that achievable with transform limited pulses. We also demonstrate how the dispersion induced by the absorption line itself leads to similar rapidly oscillating transients in the excited population. These transient population effects are applicable in any multiphoton resonant transition.
In this paper we present novel and simple pulse sequences for enhancing the intensity of forbidden or highly nonresonant optical transitions. These sequences provide a straightforward approach to circumventing the most serious limitation of optical coherent transient spectroscopy: Available laser intensities are often insufficient to excite a significant fraction of the ground state population into desired excited states, either because of large inhomogeneous broadening or, in the case of multiphoton absorption, large anharmonicities. Optical phase modulation (which can be produced by an acousto-optic modulator) or amplitude modulation (which can be produced by an interferometer) with carefully chosen pulse flip angles and delays can effectively remove even very large energy mismatches, thus permitting essentially complete population inversions arbitrarily far from resonance. Coherent averaging theory and computer calculations are used to derive particularly valuable sequences. Pumping enhancement of 103–105 (depending on individual molecular parameters) for these modulated pulse sequences are predicted. Specific applications to multiphoton pumping of local vibrational modes are discussed.
Multiphoton transitions can be reached by many routes through a continuum of virtual levels. We show that the transition probability of two-photon and multiphoton processes can be controlled by tailoring the shape of an ultrashort excitation pulse, so that the many paths leading to the final state interfere to give a desired probability amplitude. We analyze the effect of pulse shapes on N-photon absorption as well as on Raman transitions. We show theoretically that certain tailored dark pulses do not excite the system at all, while other shaped pulses induce transitions as effectively as transform limited pulses, even when their peak amplitudes are greatly reduced. These results are confirmed experimentally for two-photon transitions in atomic cesium.
We investigated numerically and experimentally the enhancement of vibrational coherence and population transfer in solution using tailored pulses. The general control mechanism is based on the precise control of the absorption after excitation with multipulses. Transient absorption was used as an experimental method to quantify the enhancement after the excitation with a shaped pump pulse in the low-pulse energy regime. A density-matrix approach was used to investigate the effect of the shaped excitation of a four-level system (two ground-state vibrational levels + two excited-state vibrational levels). Density-matrix simulation results suggest similar wavelength dependence as observed in the transient absorption experiment. The results show that enhancement of population transfer and vibrational coherence depends crucially on the overlap between the excitation pulse spectrum and the molecular absorption band.
We present and experimentally demonstrate for the first time the observation and femtosecond coherent control over the temporal evolution of a transient population that is excited via nonresonant two-photon absorption. Based on symmetry properties of the two-photon absorption process, the exciting femtosecond pulses are phase-shaped to photoinduce different evolutions of the transient excited population for a given final excited population. As a study case, we focus here on the attractive case of two-photon dark pulses that, although inducing zero final population (hence, the terminology of "dark pulses"), they induce a transient excited population during the pulse irradiation that can significantly deviate from zero. This nonzero transient population can be viewed as the bright side of such dark pulses. The symmetry-based coherent control is demonstrated first with dark pulses that we shape to induce transient excited population that at all times is kept below different target levels. Then, it is further demonstrated with pairs of dark pulses where one is rationally shaped to induce temporal evolution of the transient excited population that is the inverse of the evolution induced by the other. The work is conducted in the weak-field regime with the sodium atom as the model system. The approach developed here is general, conceptually simple, and very effective.
The interaction between the laser pulse with a small-area and a three-level atomic system is investigated.The formation and characterization of the shaped laser pulse are analyzed and the two-photon transition is studied with the shaped laser pulse.The influence of the relaxation of the excited state and the length of the shaping medium on the two-photon absorption is discussed.Based on the dispersion theory the oscillation of the transient twophoton transition is explained.The result indicates that the transition probability of two-photon absorption evolves regularly with the several values of parameters such as the length of medium(l),relaxation time(t2) and bandwidth(Δω).Meanwhile the transition probability appears in the transient oscillation.
Multiphoton transition probability can be manipulated by tailoring the ultrashort laser pulses. In this paper, we theoretically and experimentally investigate the influence of the absorption bandwidth and line shape on the coherent control of two-photon transitions in two-level system by manipulating the femtosecond laser pulse with the $\ensuremath{\pi}$ spectral phase step. A coherent feature with a coherent peak and two coherent dips can be achieved if the absorption bandwidth is less than twice of the laser spectral bandwidth. The absorption bandwidth decides the coherent peak or dip intensity, and the absorption line shape affects the symmetry of the two coherent dips.