Resonantly enhanced, degenerate four-wave mixing measurement of the cubic molecular hyperpolarizability of squaraine dyes at 700 nm

Journal Article · Thu Jul 18 04:00:00 EDT 1996 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/jp960447n· OSTI ID:380823

Tran, K; Scott, G W ^[1]; Funk, D J; Moore, D S ^[2]

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1. Univ. of California, Riverside, CA (United States)
2. Los Alamos National Lab., NM (United States)

We report the results of resonantly enhanced, degenerate four-wave mixing (DFWM) measurements of the cubic molecular hyperpolarizability coefficient ({gamma}) of four squaraine dyes. Different determinations of {gamma} were performed at 696 and 710 nm with both ultrashort (210 fs) and somewhat longer (3 ps) duration laser pulses using the forward wave geometry. Bis[4-(dimethylamino)phenyl]squaraine (H-Sq), bis[4-(dimethylamino)-2-hydroxyphenyl]squaraine (HO-Sq), bis(2,4,6-trihydroxyphenyl)squaraine (3HO-Sq), and diazulenylsquaraine (Az-Sq) were investigated as a function of concentration in liquid solutions and polymer blends, enabling the calculation of {gamma} from the measured values of the third-order nonlinear susceptibilities, {chi}{sup (3)}, of these samples. All values of {gamma} for these squaraines were found to be negative with large absolute magnitudes, up to nearly 8 x 10{sup -32} in esu `units` [9.9 x 10{sup -57} C m{sup 4} V{sup -3} (SI units)] for the real part of {gamma} for Az-Sq at 696 nm. [We discuss the conversion of esu units to SI units for the quadratic ({beta}) and cubic hyperpolarizability coefficients ({gamma}) in the Appendix of this paper, reporting our results throughout in both system of units.] Significant imaginary contributions to {gamma} were also observed for Az-Sq, but not for the other squaraines as expected from differences in absorption at these wavelengths. 49 refs., 6 figs., 3 tabs.

• OSTI ID: 380823
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 29 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ABSORPTION SPECTRA
ABUNDANCE
DYES
MEASURING METHODS
MOLECULAR STRUCTURE
OPTICAL PROPERTIES
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
POLARIZATION
SOLUTIONS