Abstract

Semiconductor quantum dots (QDs), also referred to as nanocrystals, that confine optically excited electron-hole pairs in all three space dimensions are also of considerable interest in science and engineering. Tailored patterning of QDs in a thick polymer matrix is of great interest for photonic and biomedical applications. For example, using enhanced third-order nonlinear optical responses of QDs [1], one expects optical multi-stability action from periodic QDs structures embedded in a polymer film [2]. In this work we report on the nonlinear optical properties of semiconductor CdSe QDs dispersed in an optically transparent polymer film. Z-scan and degenerate multiwave mixing (DMWM) measurements were performed to obtain effective nonlinear optical susceptablilities of the film at a wavelength of 532nm for various concentrations of CdSe QDs. It was found that the film exhibited 5th- and 7th-order nonlinearities. We also observed nonlinear Bragg diffraction from holographically patterned [3] CdSe QD-polymer nanocomposite films that exhibited the diffraction efficiency near 100% [4].

© 2011 Optical Society of America