Polarization‐resolved degenerate four‐wave mixing of CdS nanocrystals in a nonresonant region

Abstract

AbstractThe third‐order susceptibilities of various concentrations of TOPO‐passivated CdS nanocrystals (NCs) with the size near the Bohr radius were investigated using polarization‐resolved degenerate four‐wave mixing (DFWM) in a nonresonant excitation region with 532 nm wavelength and 8 ns pulse width. The second hyperpolarizabilities 〈γhxxxx 〉 and 〈γhxyyx 〉 of the CdS NCs were ∼1.25 × 10–42 m5/V2 and ∼3.66 × 10–43 m5/V2, respectively. The ratio (〈γhxyyx 〉/〈γhxxxx 〉) of the hyperpolarizabilities was ∼0.29 that indicated a large contribution of electronic polarization process to the third‐order nonlinearity of CdS NCs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)