Determination of resonant and nonresonant third-order nonlinearities of organic molecules by phase-conjugate interferometry.
We have used a phase-conjugate interferometer to determine the real and imaginary parts of the third-order hyperpolarizability of 3,3'-diethyloxadicarbocyanine iodide (DODCI) and 4-methoxy-4'-nitrostilbene (MONS) at 1064 nm. For DODCI the values are enhanced by a two-photon resonance, and the two-photon extinction coefficient is determined. However, the nonlinear loss of DODCI is dominated by linear absorption from the two-photon excited state. We could not observe linear or nonlinear absorption for the MONS solutions, and we have determined the nonresonant third-order hyperpolarizability for this molecule.
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Persoons