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

2001 ◽  
Author(s):  
Teresa Cusati ◽  
J. L. Paz ◽  
M. C. Salazar ◽  
A. J. Hernandez
Keyword(s):  
Relaxation Times ◽  
Four Wave Mixing ◽  
Wave Mixing ◽  
Strength Constant ◽  
Potential Curves

Excited state dynamics in phthalocyanines studied using degenerate four wave mixing with incoherent light

2002 ◽  
Vol 06 (03) ◽  
pp. 233-237 ◽  
Author(s):  
S. Venugopal Rao ◽  
D. Narayana Rao
Keyword(s):  
Excited State ◽  
Relaxation Times ◽  
Four Wave Mixing ◽  
Wave Mixing ◽  
Phase Relaxation ◽  
Incoherent Light ◽  
Phase Conjugate ◽  
Excited State Dynamics ◽  
Degenerate Four Wave Mixing ◽  
Population Relaxation

We present our experimental results on the measurements of excited state dynamics in phthalocyanines ( Pc , CuPc , FePc , and ZnPc ) using degenerate four wave mixing with incoherent light (DFWM-IL). Three different timescales were observed, for all samples, in the phase conjugate signal recorded as a function of delay in probe beam in the standard backward geometry. The fastest component (< 170 fs) is associated to the phase relaxation in the S n states and the slowest components (∼3-5 ps and 35-55 ps) to the vibration and population relaxation times from the S1 state. The present results are compared with those obtained with shorter pulses and various techniques for similar molecules. The consequences of such short lifetimes are also discussed in view of the strong optical limiting properties of these molecules.

Effects of spectral diffusion on the nonlinear optical properties in two- and three-state quantum systems in a four-wave mixing signal

2018 ◽  
Vol 27 (04) ◽  
pp. 1850038
Author(s):  
F. Moncada ◽  
J. L. Paz ◽  
L. Lascano ◽  
C. Costa-Vera
Keyword(s):  
Nonlinear Optical ◽  
Relaxation Times ◽  
Potential Method ◽  
Four Wave Mixing ◽  
Quantum Systems ◽  
Spectral Diffusion ◽  
Nonlinear Susceptibility ◽  
Matrix Formalism ◽  
Wave Mixing ◽  
Potential Applications

Effects of spectral diffusion on the third-order nonlinear susceptibility for two- and three-level quantum systems, immersed in a thermal reservoir, are evaluated with a four-wave mixing (FWM) signal through the density matrix formalism. For this, inhomogeneously broadened two- and three-level quantum systems are used. In these models, the distribution of natural frequencies follows a Lorentzian function. The absorptive and dispersive nonlinear optical responses are determined for the considered quantum models. The results presented in this work show potential applications in the development of optical switches and provide a potential method to measure spectral diffusion relaxation times in three-level quantum systems.

Ultrafast relaxation times of metalloporphyrins by time-resolved degenerate four-wave mixing with incoherent light

1997 ◽  
Vol 14 (10) ◽  
pp. 2710 ◽  
Author(s):  
D. Narayana Rao ◽  
S. Venugopal Rao ◽  
F. J. Aranda ◽  
D. V. G. L. N. Rao ◽  
M. Nakashima ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Four Wave Mixing ◽  
Wave Mixing ◽  
Incoherent Light ◽  
Time Resolved ◽  
Ultrafast Relaxation ◽  
Degenerate Four Wave Mixing

Hole induced four wave mixing and intervalence band relaxation times in p-GaAs and p-Ge

1985 ◽  
Vol 56 (6) ◽  
pp. 489-491 ◽  
Author(s):  
S.Y. Yuen ◽  
P.A. Wolff ◽  
L.R. Ram-Mohan ◽  
R.A. Logan
Keyword(s):  
Relaxation Times ◽  
Four Wave Mixing ◽  
Wave Mixing

Four-wave mixing signal intensity: Relaxation time effects on the absorptive and dispersive optical properties in a two-level system

2015 ◽  
Vol 24 (02) ◽  
pp. 1550023
Author(s):  
J. L. Paz ◽  
Luis G. Rodríguez ◽  
Cesar Costa-Vera
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Dipole Moments ◽  
Relaxation Times ◽  
Four Wave Mixing ◽  
Wave Mixing ◽  
Level System ◽  
Time Effects ◽  
Frequency Space ◽  
Signal Response

A study of the effects of relaxation times on the Four-Wave Mixing (FWM) signal response in frequency space for a two-level system is presented where the collisional effects of the solvent and the presence of the electromagnetic field are considered. The model is a generalization of the conventional two-level approach in that it includes a simplified description of the molecular structure associated with the non-zero permanent dipole moments. Significant changes in both the FWM-intensity and nonlinear optical properties are observed, due mainly to changes in the ratio between the longitudinal and transversal relaxation times.

SOLVENT COLLISIONAL EFFECTS IN FOUR-WAVE MIXING

2012 ◽  
Vol 21 (02) ◽  
pp. 1250016 ◽  
Author(s):  
A. MASTRODOMENICO ◽  
M. A. IZQUIERDO ◽  
J. L. PAZ
Keyword(s):  
Electromagnetic Field ◽  
Random Function ◽  
Molecular System ◽  
Relaxation Times ◽  
Four Wave Mixing ◽  
Collective Effects ◽  
Thermal Bath ◽  
Wave Mixing ◽  
Stochastic Effects ◽  
Upper Level

The stochastic effects of a thermal bath on a two-level molecular system interacting with a classical electromagnetic field are considered. The collective effects are modeled as a random Bohr frequency, whose manifestation is the broadening of the upper level according to a prescribed random function. A methodology based in cumulant expansions to obtain the average in the Fourier components associated with the coherence and populations, calculated by Optical Stochastic Bloch Equations (OSBE), is employed. The Four-wave mixing signal intensity as a function of the detuning of the pump beam, parametrized by the ratio of the relaxation times and other variables, is analyzed.

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