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Journal of Optics A Pure and Applied Optics

Study of force constants of crossed curves on four-wave mixing signals

Teresa Cusati, José Luis Paz, Emilio Squitieri

Published Aug 21, 2003• 0 citations
Publisher

Abstract

In this work we have studied the effects on a four-wave mixing (FWM) signal of different apertures of two crossed harmonic curves in an intramolecular coupling model. These apertures are measured using the quotient between the resonant frequencies of two curves, Δ = 0 /ω 0 . We observed changes in intensity and position of the peaks present in the FWM signal spectra due to the variations in Δ. These changes are directly related to the behaviour of the resonant frequency and the dipole moments of the coupled states with the parameter Δ.

DOI
10.1088/1464-4258/5/5/390

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Influence of changes in dipole moments of a system with intramolecular coupling on the four-wave mixing signal

Teresa Cusati, José Luis Paz

In this work we study the changes in the Four-Wave Mixing (FWM) signal with the modification of the permanent and transition dipolar moments of states in a coupled basis (under the inclusion of intramolecular coupling phenomenon), due to the changes in different parameters, such as coupling parameters v and Vo, strength constant Δ, and transition dipolar moment between the uncoupled states m12. Changes in the intensity and position of the resonances in the FWM signal spectra are observed with the variation in the parameters mentioned above.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Nov 18, 2003•0 citations

Modification in the relaxation times and strength constant of potential curves in four-wave mixing

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In this work we have studied the changes in the Four-Wave Mixing (FWM) signal with the changes in the ratio between the longitudinal and transversal relation times T1/T2. Moreover, we have studied too the modifications in the FWM signal with the changes in the strength constant of the crossed harmonic potential curves that describe the two- levels system employed to this study. We have included the permanent dipolar moments of the states in the uncoupled basis. The rotating wave approximation is neglected to observe the process out of the resonance region. We observed changes in the shape, intensity and position in the resonances of the FWM signal spectra, with the changes in the ratio T1T2 and the strength constant (delta) .© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Aug 14, 2001•0 citations

Modifications in the Maximal Intensity of Four-Wave Mixing Signal under the Changes of Vibronic Coupling Conditions #

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Motivation. The spectroscopic analysis of the behavior of the nonlinear signal response of systems including electronic levels is described by the coupling parameters of crossed harmonic potential curves. Method. Changes in the Four–Wave Mixing (FWM) signal intensity are originated by the modifications of the dipole moments in the new coupled basis due to variation of the parameters V0 (energetic difference between the minima), v (coupling parameter) and G (strength constant) corresponding to the crossed states involved. The permanent dipole moments of the states in the uncoupled basis have been included and the Rotating–Wave Approximation is neglected in order to observe the processes out of the resonance region. The calculation method is based in the Liouville–von Neumann formalism for the density matrix, where the Conventional Optical Bloch Equations are solved in Fourier space to obtain the density matrix elements associated with the Macroscopic Polarization responsible of the FWM signal. Results. Variation in the coupling parameters generates modifications in the dipole moments of the coupled states. These modifications induce changes in the intensity values of the FWM signal, including the nullity of the dipole moments producing the nullity of the nonlinear signal. Mathematical expressions are obtained to interpret these results. Conclusions. Changes in the characteristic coupling parameters induce modifications on the crossed potential curves, and consequently, on the nonlinear response and intensity.

•Jan 1, 2004•1 citation

Effects of the dipole moments behavior on a vibronic coupling model for the four‐wave mixing signal

Teresa Cusati, José Luis Paz, A. J. Hernández

Abstract In the present work, we have studied modifications in the transition and permanent dipole moments of states in a coupled basis (including vibronic coupling) due to variations in the transition dipole moment between the uncoupled states, m 12 , as a function of the parameter δ = $\tilde{\omega}$ 0 /ω 0 (relative aperture) of the potential‐energy curves of the states involved. Modifications in the slopes of the transition and permanent dipole moments of the coupled states and changes in the magnitude of maximal intensity of the four‐wave mixing (FWM) signal are observed due to variations in these parameters. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004

International Journal of Quantum Chemistry•Jan 1, 2004•2 citations

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A study has been made of the effect of relaxation times on the four-wave mixing (FWM) signal response in frequency space for a two-level system where intramolecular coupling is explicitly taken into account within a vibronic model. The model is a generalization of the conventional two-level approach in that it includes a simplified description of the molecular structure and the explicit consideration of permanent dipole moments. Significant changes in both the intensity and shape of the peaks of the FWM spectrum are observed, due mainly to changes in the ratio between the longitudinal and transversal relaxation times, T 1/T 2.

Molecular Physics•May 20, 2002•1 citation

Study of the nonlinear optical responses in the Four-wave mixing signal in saturation regimen of a two-level system with intramolecular coupling

José Luis Paz, Eleana Ruiz-Hinojosa, Ysaías J. Alvarado +5 more

We consider the Four-Wave mixing (FWM) signal and the effects of the pump beam on the nonlinear optical responses of a two-level system where intramolecular coupling is modelled by two coupled harmonic electronic potentials, displaced both in their equilibrium minimum position and energy. We investigate the modifications introduced in the FWM signal, considering a simple representation for the vibrational structure and including molecular electronic states with nonzero permanent dipole moments. The critical quantities for this analysis are the transition and permanent dipole moments, which depend strongly on the intramolecular coupling. Our results show how both absorption and dispersion are affected by the vibronic coupling.

Journal of Modern Optics•Jun 24, 2020•3 citations
In this work we have studied the effects on a four-wave mixing (FWM) signal of different apertures of two crossed harmonic curves in an intramolecular coupling model. These apertures are measured using the quotient between the resonant frequencies of two curves, Δ = 0 /ω 0 . We observed changes in intensity and position of the peaks present in the FWM signal spectra due to the variations in Δ. These changes are directly related to the behaviour of the resonant frequency and the dipole moments of the coupled states with the parameter Δ.
In this work we study the changes in the Four-Wave Mixing (FWM) signal with the modification of the permanent and transition dipolar moments of states in a coupled basis (under the inclusion of intramolecular coupling phenomenon), due to the changes in different parameters, such as coupling parameters v and Vo, strength constant Δ, and transition dipolar moment between the uncoupled states m12. Changes in the intensity and position of the resonances in the FWM signal spectra are observed with the variation in the parameters mentioned above.
In this work we have studied the changes in the Four-Wave Mixing (FWM) signal with the changes in the ratio between the longitudinal and transversal relation times T1/T2. Moreover, we have studied too the modifications in the FWM signal with the changes in the strength constant of the crossed harmonic potential curves that describe the two- levels system employed to this study. We have included the permanent dipolar moments of the states in the uncoupled basis. The rotating wave approximation is neglected to observe the process out of the resonance region. We observed changes in the shape, intensity and position in the resonances of the FWM signal spectra, with the changes in the ratio T1T2 and the strength constant (delta) .© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Motivation. The spectroscopic analysis of the behavior of the nonlinear signal response of systems including electronic levels is described by the coupling parameters of crossed harmonic potential curves. Method. Changes in the Four–Wave Mixing (FWM) signal intensity are originated by the modifications of the dipole moments in the new coupled basis due to variation of the parameters V0 (energetic difference between the minima), v (coupling parameter) and G (strength constant) corresponding to the crossed states involved. The permanent dipole moments of the states in the uncoupled basis have been included and the Rotating–Wave Approximation is neglected in order to observe the processes out of the resonance region. The calculation method is based in the Liouville–von Neumann formalism for the density matrix, where the Conventional Optical Bloch Equations are solved in Fourier space to obtain the density matrix elements associated with the Macroscopic Polarization responsible of the FWM signal. Results. Variation in the coupling parameters generates modifications in the dipole moments of the coupled states. These modifications induce changes in the intensity values of the FWM signal, including the nullity of the dipole moments producing the nullity of the nonlinear signal. Mathematical expressions are obtained to interpret these results. Conclusions. Changes in the characteristic coupling parameters induce modifications on the crossed potential curves, and consequently, on the nonlinear response and intensity.
Abstract In the present work, we have studied modifications in the transition and permanent dipole moments of states in a coupled basis (including vibronic coupling) due to variations in the transition dipole moment between the uncoupled states, m 12 , as a function of the parameter δ = ω~\tilde{\omega}ω~ 0 /ω 0 (relative aperture) of the potential‐energy curves of the states involved. Modifications in the slopes of the transition and permanent dipole moments of the coupled states and changes in the magnitude of maximal intensity of the four‐wave mixing (FWM) signal are observed due to variations in these parameters. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
A study has been made of the effect of relaxation times on the four-wave mixing (FWM) signal response in frequency space for a two-level system where intramolecular coupling is explicitly taken into account within a vibronic model. The model is a generalization of the conventional two-level approach in that it includes a simplified description of the molecular structure and the explicit consideration of permanent dipole moments. Significant changes in both the intensity and shape of the peaks of the FWM spectrum are observed, due mainly to changes in the ratio between the longitudinal and transversal relaxation times, T 1/T 2.
We consider the Four-Wave mixing (FWM) signal and the effects of the pump beam on the nonlinear optical responses of a two-level system where intramolecular coupling is modelled by two coupled harmonic electronic potentials, displaced both in their equilibrium minimum position and energy. We investigate the modifications introduced in the FWM signal, considering a simple representation for the vibrational structure and including molecular electronic states with nonzero permanent dipole moments. The critical quantities for this analysis are the transition and permanent dipole moments, which depend strongly on the intramolecular coupling. Our results show how both absorption and dispersion are affected by the vibronic coupling.