Linear optical susceptibility

Non-linear optical susceptibilities and experimental methods to evaluate x and p. 153... 

Many of the different susceptibilities in Equations (2.165)-(2.167) correspond to important experiments in linear and nonlinear optics. x<(>> describes a possible zero-order (permanent) polarization of the medium j(1)(0 0) is the first-order static susceptibility which is related to the permittivity at zero frequency, e(0), while ft> o>) is the linear optical susceptibility related to the refractive index n" at frequency to. Turning to nonlinear effects, the Pockels susceptibility j(2)(- to, 0) and the Kerr susceptibility X(3 —to to, 0,0) describe the change of the refractive index induced by an externally applied static field. The susceptibility j(2)(—2to to, to) describes frequency doubling usually called second harmonic generation (SHG) and j(3)(-2 to, to, 0) describes the influence of an external field on the SHG process which is of great importance for the characterization of second-order NLO properties in solution in electric field second harmonic generation (EFISHG). 

Qualitative trends for jS in simple model systems two-centre model system one-dimensional NLO-phores 143 Three-centre model system (C2 and D h symmetry) 145 Local field factors and effective polarizabilities the reaction field model Non-linear optical susceptibilities and experimental methods to evaluate and /3 153... 

The real and imaginary parts of third-order non-linear optical susceptibilities of 10 M solutions of Fe2(CO)6 (/t3-E3P) CpCr(GO)2 (E = S or Se) and the well-known precursor clusters Fe3(CO)9(/i3-E)2 in toluene were measured using Z-scan and ARINS techniques, respectively. The mixed metal clusters display nearly three times the second molar hyperpolarizability values of the corresponding Fes precursors. The results suggest a rich potential of mixed metal, mixed non-metal class of clusters as materials exhibiting large non-linearity. 

S.S. Dimov, L.l. Pavlov, K.V. Stamenov, G.B. Altshuller, Non-linear optical susceptibility measurement of an autoionizing-like resonance in atoms, Opt. Quantum Electron. 15 (1983) 305. 

Non-centrosymmetric Y-type LB films of DCANP can easily be prepared in a thickness more than sufficient for optical waveguiding. Their non-linear optical susceptibility in transmission is approximately 25% of that of LiNbOs and there is no phase mismatch, up to a thickness of 270 bilayers. Multilayers show a strong optical and non-linear optical anisotropy with respect to the dipping direction, which is a consequence of the transfer process. 

An interesting finding with Copolys 1-3, Copoly-5 and PAE-2 was that they gave (third-order non-linear optical susceptibility) values of 3-5 x 10 " esu. Figure 5.14 shows the UV-vis spectrum and profile of the CT-type copolymers. 

The requirement of acentricity and an examination of the atoms and molecular groups (and their disposition) have been useful in the search for new nonlinear optical materials. In addition, the Miller delta rule, which relates the magnitude of the nonlinear optical susceptibility d to the linear optical susceptibility x, is valuable in gaining information on the strength of the nonlinear effects to be expected from a given material. Miller s equation is... 

As proposed by Munn and Hurst [74, 75], an elegant alternative is to employ the generalization of the electrostatic dipole interaction scheme proposed by SUber-stein for atoms [76, 77] to molecules, which consists in evaluating first the local field via the Lorentz-factor tensor [78] and then the macroscopic linear and NLO susceptibilities from the molecular responses calculated using quantum chemistry methods. To alleviate the limitations of the point dipole approximation, the molecule and its molecular responses are usually partitioned in submolecules [79]. Within this approach, the linear optical susceptibility tensor for a crystal with Z molecules labeled k (or Z submolecules labeled kj) per unit cell with a volume V reads ... 

In a non-exhaustive literature search, a brief account is given here on the study of phonon and its vibrations. Corso et al. did an extensive study of density functional perturbation theory for lattice dynamics calculations in a variety of materials including ferroelectrics [93]. They employed a nonlinear approach to mainly evaluate the exchange and correlation energy, which were related to the non-linear optical susceptibility of a material at low frequency [94], The phonon dispersion relation of ferroelectrics was also studied extensively by Ghosez et al. [95, 96] these data were, however, related more with the structure and metal-oxygen bonds rather than domain vibrations or soliton motion. In a very interesting work, a second peak in the Raman spectra was interpreted by Cohen and Ruvalds [97] as evidence for the existence of bound state of the two phonon system and the repulsive anharmonic phonon-phonon interaction which splits the bound state off the phonon continuum was estimated for diamond. 

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