Abstract

We have designed a hyper-Rayleigh scattering scheme to measure six scalar invariants of the squared hyperpolarizability tensor ${\beta }^2.$ Our theoretical approach expresses the rotational invariants of the irreducible β components as scalars, which eliminates the need for difficult frame transformations. We applied our scheme to several conjugated chiral molecules and found that there are significant Kleinman-disallowed pseudotensor contributions to their hyperpolarizability. These components, along with a large optical rotation and the results of quantum-chemical calculations, indicate a handed nonplanar delocalization of the charge-transfer system in such molecules as predicted by quantum-chemical calculations and are expected to lead to macroscopic second-harmonic generation in axially aligned polymer materials. Pseudotensor contributions to the hyperpolarizability in chiral molecules were found to be as large as the vector contribution in $p$-nitroaniline. We qualitatively investigated the dispersion in the Kleinman-disallowed components and confirmed that these components are smaller at longer wavelengths.

© 1998 Optical Society of America

Measurements of the hyperpolarizability tensor by means of hyper-Rayleigh scattering

V. Ostroverkhov, R. G. Petschek, K. D. Singer, L. Sukhomlinova, R. J. Twieg, S.-X. Wang, and L. C. Chien
J. Opt. Soc. Am. B 17(9) 1531-1542 (2000)

Control of multiphoton excited emission and phase retardation in Kleinman-disallowed hyper-Rayleigh scattering measurements

Yeheng Wu, Guilin Mao, Haowen Li, Rolfe G. Petschek, and Kenneth D. Singer
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Unique determination of the hyperpolarizability tensor ratio through depolarized hyper-Rayleigh scattering under an external electric field

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J. Opt. Soc. Am. B 19(7) 1620-1626 (2002)

Multipolar molecules and multipolar fields: probing and controlling the tensorial nature of nonlinear molecular media

S. Brasselet and J. Zyss
J. Opt. Soc. Am. B 15(1) 257-288 (1998)

Second-harmonic generation in nonpolar chiral materials: relationship between molecular and macroscopic properties

Victor Ostroverkhov, Kenneth D. Singer, and Rolfe G. Petschek
J. Opt. Soc. Am. B 18(12) 1858-1865 (2001)