Abstract

Photopolymerizable nanoparticle-polymer composites [1] are a new class of photonic materials, in which multi-dimensional photonic lattice structures can be constructed optically by holographic assembly of nanoparticles [2]. Multiplexed holographic digital data page storage [3] and cold neutron beam splitter/mirror actions [4] were demonstrated by use of SiO₂ nanoparticles-polymer composite films. We also demonstrated the construction of volume Bragg grating structures in a semiconductor CdSe quantum dots (QDs) dispersed polymer film with diffraction efficiency near 100% [5]. Recently, we reported on the nonlinear optical properties of such semiconductor CdSe QD-polymer composites. We showed that Z-scan and forward degenerate multiwave mixing (DMWM) measurements revealed the occurrence of third- and high-order optical nonlinearities at 532 nm below the quantum-confined electron-hole transition [6]. Nonlinear Bragg diffraction from a fixed volume Bragg grating was also observed [7]. In this work we report on the effect of surface deep traps on optical nonlinearities causing nonlinear transmission and DMWM self-diffraction from CdSe QD-polymer nanocomposites.

© 2013 IEEE