Optically tailored access to metastable electronic states

Andrews, Davıd L.

doi:10.1016/j.cplett.2013.10.067

Cited by 5 publications

(4 citation statements)

References 19 publications

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“…Following electronic excitation of a molecule-and in the absence of phosphorescence arising from inter-system crossing-there are usually two major relaxation routes: One is fluorescent emission, the subject of this section, and the other is energy transfer to a second 'acceptor' molecule (discussed in Section 5). Since, in terms of quantum electrodynamics, light emission is simply time- It is interesting that excitation of a molecule to a metastable state, i.e., one that is one-photon forbidden by orbital symmetry properties, may become possible by input of the off-resonant beam, since the resulting three-photon mechanism for access to a conventionally symmetry-unfavorable state could then become allowed [55]. This enables a population of a 'dark' state-a transition that would otherwise be improbable.…”

Section: Laser-modified Fluorescencementioning

confidence: 99%

Off-Resonance Control and All-Optical Switching: Expanded Dimensions in Nonlinear Optics

Forbes

Andrews

2019

Applied Sciences

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The theory of non-resonant optical processes with intrinsic optical nonlinearity, such as harmonic generation, has been widely understood since the advent of the laser. In general, such effects involve multiphoton interactions that change the population of each input optical mode or modes. However, nonlinear effects can also arise through the input of an off-resonant laser beam that itself emerges unchanged. Many such effects have been largely overlooked. Using a quantum electrodynamical framework, this review provides detail on such optically nonlinear mechanisms that allow for a controlled increase or decrease in the intensity of linear absorption and fluorescence and in the efficiency of resonance energy transfer. The rate modifications responsible for these effects were achieved by the simultaneous application of an off-resonant beam with a moderate intensity, acting in a sense as an optical catalyst, conferring a new dimension of optical nonlinearity upon photoactive materials. It is shown that, in certain configurations, these mechanisms provide the basis for all-optical switching, i.e., the control of light-by-light, including an optical transistor scheme. The conclusion outlines other recently proposed all-optical switching systems.

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Section: Laser-modified Fluorescencementioning

confidence: 99%

Off-Resonance Control and All-Optical Switching: Expanded Dimensions in Nonlinear Optics

Forbes

Andrews

2019

Applied Sciences

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“…In recent studies, the effect of an off‐resonant laser beam in modifying the conventional one‐ and two‐photon absorption processes via higher‐order corrections has been examined. Metastable energy levels previously prohibited by symmetry now participate, providing increased possibilities for optical tuning and control …”

Section: Multi‐photon Processesmentioning

confidence: 99%

Quantum electrodynamics effects in atoms and molecules

Salam

2014

WIREs Comput Mol Sci

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Quantum electrodynamics (QED) is the fundamental theory describing the interaction of electrons and photons. Its characteristic feature is that both radiation and matter are treated quantum mechanically. For almost all atomic and molecular systems, which contain bound electrons moving at velocities considerably less than that of light, a non-relativistic formulation of QED is appropriate. Termed molecular QED, its Hamiltonian operator can be constructed by starting from the classical Lagrangian function for the interaction of a charged particle with a radiation field on applying the variational calculus and carrying out the canonical quantization procedure. It is shown how the minimal-coupling Lagrangian can be transformed to the chemically advantageous multipolar Hamiltonian in which matter couples to radiation directly through molecular multipole moments, with the ensuing interaction strictly causal. Applications include evaluation of transition rates for one-and two-photon absorption, spontaneous and stimulated emission, and signal intensities for second-and third-harmonic generation. Fundamental intermolecular interactions examined include resonance energy transfer, the van der Waals dispersion potential, and the change in energy shift of the pair induced by intense external radiation. The non-relativistic contribution to the Lamb shift is also extracted. It is shown how a number of the above mentioned processes may be attributed to fluctuations of the vacuum electromagnetic field, which possesses zero-point energy, a signature QED effect that has widespread implications for the structural and dynamical properties of atoms and molecules.

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“…2. A strong static electric field, or intensive laser radiation which mixes the parities of molecular rovibronic states due to the Stark effect is applied (see [11][12][13][14] and references therein). 3.…”

Section: Introductionmentioning

confidence: 99%

Hyperfine interaction in molecular iodine between the $0_{{\rm g}}^{+}$, 1_u and $0_{{\rm u}}^{-}$ states correlating with the I(²P_1/2) + I(²P_1/2) dissociation limit

Akopyan

Baturo

Lukashov

et al. 2014

J. Phys. B: At. Mol. Opt. Phys.

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The three-step three-color laser population of the I2(β1g, νβ, Jβ and , νD, JD) rovibronic states via those of the and 1u, (bb) states, correlating with the second and third dissociation limits of the valence states, has been used for the study of mechanisms of optical transitions involved in the population of the β1g, νβ, Jβ rovibronic states. It has been shown that the 1u(bb) ← transition is allowed due to hyperfine interactions of the 1u(bb), ν1u, J1u and (bb), ν0, J0 rovibronic states, though energy gaps between these pairs of the states are huge, greater than 0.7 cm−1. The ΔJ = ±2 lines observed in the β1g − 1u(bb) transition are also due to hyperfine interaction of the 1u(bb), ν1u, J1u and (bb), ν0, J0 rovibronic states. It has been also shown that the 1u(bb) ← transition cannot be attributed either to magnetic dipole or to electric quadrupole transitions. Contributions from the Stark effect in a strong laser field and from possible production of the I2(X)… I2(B) colliding pairs to mechanism of the 1u(bb) − transition are negligible.

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Optically tailored access to metastable electronic states

Cited by 5 publications

References 19 publications

Off-Resonance Control and All-Optical Switching: Expanded Dimensions in Nonlinear Optics

Off-Resonance Control and All-Optical Switching: Expanded Dimensions in Nonlinear Optics

Quantum electrodynamics effects in atoms and molecules

Hyperfine interaction in molecular iodine between the $0_{{\rm g}}^{+}$, 1_u and $0_{{\rm u}}^{-}$ states correlating with the I(²P_1/2) + I(²P_1/2) dissociation limit

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Optically tailored access to metastable electronic states

Cited by 5 publications

References 19 publications

Off-Resonance Control and All-Optical Switching: Expanded Dimensions in Nonlinear Optics

Off-Resonance Control and All-Optical Switching: Expanded Dimensions in Nonlinear Optics

Quantum electrodynamics effects in atoms and molecules

Hyperfine interaction in molecular iodine between the $0_{{\rm g}}^{+}$, 1u and $0_{{\rm u}}^{-}$ states correlating with the I(2P1/2) + I(2P1/2) dissociation limit

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Hyperfine interaction in molecular iodine between the $0_{{\rm g}}^{+}$, 1_u and $0_{{\rm u}}^{-}$ states correlating with the I(²P_1/2) + I(²P_1/2) dissociation limit