Stimulated Orientational Scattering

I. C. Khoo, Y. Liang and H. Li, "Polarization Switching by Stimulated Orientational Scattering in Birefringent Nonlinear Nematic Liquid Crystal Film," lEEE-Lasers and Electro-Optics Society Technical Meeting, San Jose, CA (November 1993). 

Accordingly, unlike most nonhnear optical materials, liquid crystals enable optical wave mixings to occur with high efficiency in the visible as well as infrared regime. In this section, we discuss two exemplary wave mixing processes in hquid crystals stimulated orientational scatterings and optical phase conjugation processes. 

Stimulated Orientational Scattering and Polarization Self-Switching Steady State... 

Figure 12.8. Experimental set up for observing stimulated orientational scattering in a nematic liquid crystal. Photos show the transmitted pump (e-wave) and stimulated (o-wave) at low and high input laser power.

In a recent study, the coupled electromagnetic waves and director axis reorientation equations, cf. Chapter 11, for the stimulated orientation scattering process are solved by treating all the molecular and optical parameters involved as spatial-temporal variables. For example, the director axis reorientation angle 0 is represented as 0(z,t)=2 (r)sin( 7tz/Z). In that case, the torque balance equation becomes... 

Etchegoin, P., and R. T. Phillips. 1997. Stimulated orientational scattering and third-order nonlinear optical processes in nematic liquid crystals. Phys. Rev.E. 55 5603-5612. 

Khoo, I. C. and Y. Liang, 1995. Observation of stimulated orientational scattering and cross-polarized self-starting phase-conjugation in a nematic liquid-crystal film. Opt Lett. 20 130-132. 

Khoo, lam Choon,Jianwu Ding, and Andres Diaz. 2005. Dynamics of cross-polarization stimulated orientation scattering in nematic Uquid crystal film. J. Opt. Soc. Am. B. 22 844-851. 

Band, Y.B. and Yulienne, P.S. (1992). Complete alignment and orientation of atoms and molecules by stimulated Raman scattering with temporally shifted lasers, J. Chem. Phys., 96, 3339-3341. 

The dynamical nature of nonlinear responses (33) can be better emphasized by writing down the explicit time-dependent equations describing a given interaction, such as the transient stimulated Raman scattering (34,35) or the optical Kerr effect (36), which reveal the time-dependent memory of the initial coherence, phase memory and orientational alignment imposed on the system during that ps interaction. In concluding this article, we focus on the time-dependence of the nonlinear quantum electronic responses of molecular systems to intense ps and fs polarized laser fields, and the role of the molecular dynamics of the liquid in the persistence of the memory of the nonlinear interaction. 

Khoo, I. C., and Y. Liang. 2000. Stimulated orientational and thermal scatterings and selfstarting optical phase conjugation with nematic liquid crystals. Phys. Rev. E. 62 6722-6733. 

The nature of reaction products and also the orientation of adsorbed species can be studied by atomic beam methods such as electron-stimulated desorption (ESD) [49,30], photon-stimulated desoiption (PDS) [51], and ESD ion angular distribution ESDIAD [51-54]. (Note Fig. VIII-13). There are molecular beam scattering experiments such... 

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