Active control of product selection in a chemical reaction: a view of the current scene

Rice, Stuart A.; Shah, Suhail P.

doi:10.1039/b109911f

Cited by 25 publications

(19 citation statements)

References 72 publications

(88 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The solid arrows in the diagrams shown in Figure 1 correspond to n e Àiwt interactions (photon annihilation or bra interaction) and are given by E n while the dashed arrows correspond to m e iwt interactions (photon creation or ket interaction) and are given by E* m in Equation (5). The Fourier image of this field defines the spectral amplitude of effective nonlinear electric field given in Equation (6):…”

Section: The Effect Of Phase Modulation On Nonlinear Processesmentioning

confidence: 98%

Systematic Control of Nonlinear Optical Processes Using Optimally Shaped Femtosecond Pulses

Lozovoy¹,

Dantus²

2005

ChemPhysChem

View full text Add to dashboard Cite

This article reviews experimental efforts to control multiphoton transitions using shaped femtosecond laser pulses, and it lays out the systematic study being followed by us for elucidating the effect of phase on nonlinear optical laser-molecule interactions. Starting with a brief review of nonlinear optics and how nonlinear optical processes depend on the electric field inducing them, a number of conclusions can be drawn directly from analytical solutions of the equations. From a Taylor expansion of the phase in the frequency domain, we learn that nonlinear optical processes are affected only by the second- and higher-order terms. This simple result has significant implications on how pulse-shaping experiments are to be designed. If the phase is allowed to vary arbitrarily as a continuous function, then an infinite redundancy that arises from the addition of a linear phase function across the spectrum with arbitrary offset and slope could prevent us from carrying out a closed-loop optimization experiment. The early results illustrate how the outcome of a nonlinear optical transition depends on the cooperative action of all frequencies in the bandwidth of a laser pulse. Maximum constructive or destructive interference can be achieved by programming the phase using only two phase values, 0 and pi. This assertion has been confirmed experimentally, where binary phase shaping (BPS) was shown to outperform other alternative functions, sometimes by at least on order of magnitude, in controlling multiphoton processes. Here we discuss the solution of a number of nonlinear problems that range from narrowing the second harmonic spectrum of a laser pulse to optimizing the competition between two- and three-photon transitions. This Review explores some present and future applications of pulse shaping and coherent control.

show abstract

Section: The Effect Of Phase Modulation On Nonlinear Processesmentioning

confidence: 98%

Systematic Control of Nonlinear Optical Processes Using Optimally Shaped Femtosecond Pulses

Lozovoy¹,

Dantus²

2005

ChemPhysChem

View full text Add to dashboard Cite

show abstract

“…Since the recognition that the Chen-Shapiro-Brumer strong field approach 2 to the control of photodissociation can be regarded as a five-level extension of STIRAP, 5,6 there has been a renewed interest in studies of controlled molecular dynamics from a STIRAP perspective. [7][8][9][10][11][12][13][14][15] Two features inherent to STIRAP-like dynamics are particularly appealing to theoretical studies. First, the molecular dynamics associated with a STIRAP-like process, although subject to strong control fields, can be described by perturbative analytical treatments, the validity of which originates from the weak nonadiabaticity rather than weak fields.…”

Section: Introductionmentioning

confidence: 99%

Adiabatic population transfer in a liquid: Taking advantage of a decaying target state

Gong

Rice

2004

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

The feasibility of efficient population transfer between an initial state and a decaying target state of the same parity without populating an intermediate state, in the presence of large-amplitude stochastic energy level fluctuations that mimic the dephasing in a solute molecule due to the influence of a solvent, is demonstrated theoretically. In particular, it is shown that a decaying target state, whose decay rate constant is large compared with the band width of picosecond laser pulses but small compared with the associated peak Rabi frequencies, can dramatically suppress the dephasing-induced nonadiabaticity associated with the dynamics of population transfer, resulting in, irrespective of the correlation time of stochastic energy level fluctuations, negligible population in the intermediate state and complete population transfer to the decaying target state. These results should further motivate experimental studies of optical control of molecular dynamics in a liquid. An interesting connection between our results and the quantum Zeno and anti-Zeno effects is also discussed.

show abstract

“…The operators U k were evaluated using Eq. (7), and they differ only in the RF amplitudes involved. In NMR spectrometers the frequency and duration of the pulse do not vary as a function of position, and although the absolute phase does, this phase is unobservable here since the same RF coil is used for both transmission and reception.…”

Section: A Incoherent Processes In Nmr Spectroscopymentioning

confidence: 99%

Robust control of quantum information

Pravia

Boulant

Emerson

et al. 2003

The Journal of Chemical Physics

View full text Add to dashboard Cite

Errors in the control of quantum systems may be classified as unitary, decoherent and incoherent. Unitary errors are systematic, and result in a density matrix that differs from the desired one by a unitary operation. Decoherent errors correspond to general completely positive superoperators, and can only be corrected using methods such as quantum error correction. Incoherent errors can also be described, on average, by completely positive superoperators, but can nevertheless be corrected by the application of a locally unitary operation that "refocuses" them. They are due to reproducible spatial or temporal variations in the system's Hamiltonian, so that information on the variations is encoded in the system's spatiotemporal state and can be used to correct them. In this paper liquid-state nuclear magnetic resonance (NMR) is used to demonstrate that such refocusing effects can be built directly into the control fields, where the incoherence arises from spatial inhomogeneities in the quantizing static magnetic field as well as the radio-frequency control fields themselves. Using perturbation theory, it is further shown that the eigenvalue spectrum of the completely positive superoperator exhibits a characteristic spread that contains information on the Hamiltonians' underlying distribution.

show abstract

Active control of product selection in a chemical reaction: a view of the current scene

Cited by 25 publications

References 72 publications

Systematic Control of Nonlinear Optical Processes Using Optimally Shaped Femtosecond Pulses

Systematic Control of Nonlinear Optical Processes Using Optimally Shaped Femtosecond Pulses

Adiabatic population transfer in a liquid: Taking advantage of a decaying target state

Robust control of quantum information

Contact Info

Product

Resources

About