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.

SYMMETRY PROPERTIES IN THE STUDY OF THE RAYLEIGH-TYPE OPTICAL MIXING SIGNAL IN PRESENCE OF A THERMAL BATH

2013 ◽  
Vol 22 (01) ◽  
pp. 1350007
Author(s):  
J. L. PAZ ◽  
A. MASTRODOMENICO ◽  
M. A. IZQUIERDO
Keyword(s):  
Electromagnetic Field ◽  
Molecular System ◽  
Thermal Bath ◽  
Bloch Equations ◽  
System A ◽  
Symmetry Properties ◽  
Intensity Response ◽  
Optical Mixing ◽  
Cumulant Expansions

In this work are studied the symmetry properties of the Rayleigh-type optical mixing signal of a two-level molecular system immersed in a thermal bath and irradiated by a classical electromagnetic field. The solvent induces a random shift of the Bohr frequency in the molecular system. A methodology based in cumulant expansions is employed to obtain the average of the coherences, populations, and susceptibilities of Fourier components associated, calculated by the optical stochastic Bloch equations. These symmetry properties show the dependence of the measured spectra with the variations in the frequencies of the incident fields. Our results show that the inclusion of the thermal bath diminishes the intensity response as well it promotes the loss of the symmetry properties, compared with the same results in the absence of the bath.

ULTRASLOW SOLITONS VIA FOUR-WAVE MIXING IN A CRYSTAL OF MOLECULAR MAGNETS

2009 ◽  
Vol 23 (07) ◽  
pp. 989-1004
Author(s):  
LIUGANG SI ◽  
XINYOU LÜ ◽  
PEIJUN SONG ◽  
JIBING LIU
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Group Velocity ◽  
Electromagnetic Fields ◽  
Continuous Wave ◽  
Four Wave Mixing ◽  
Molecular Magnets ◽  
Wave Mixing ◽  
Bright Solitons ◽  
Rotating Wave

The authors theoretically investigate the formation of ultraslow dark and bright solitons via four-wave mixing (FWM) in a crystal of molecular magnets in the presence of a uniform d.c. magnetic field, where two strong continuous wave pump electromagnetic fields and a weak-pulsed probe electromagnetic field produce a pulsed FWM electromagnetic field. By solving the Maxwell–Schrödinger equations under the slowly varying envelope approximation and rotating-wave approximations, we demonstrate that both the weak-pulsed probe and FWM electromagnetic fields can evolve into dark and bright solitons with the same shape and the same ultraslow group velocity.

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.

Propagation of the four-wave mixing signal immersed in a thermal bath

2013 ◽  
Author(s):  
M. A. Izquierdo ◽  
A. Mastrodomenico ◽  
J. L. Paz
Keyword(s):  
Four Wave Mixing ◽  
Thermal Bath ◽  
Wave Mixing

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.

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