Table of Contents
Journal of Nanoscience
Volume 2014, Article ID 623742, 7 pages
http://dx.doi.org/10.1155/2014/623742
Research Article

Size Dependent Optical Nonlinearity and Optical Limiting Properties of Water Soluble CdSe Quantum Dots

International School of Photonics, Cochin University of Science and Technology, Cochin, Kerala 682022, India

Received 4 July 2014; Accepted 4 November 2014; Published 26 November 2014

Academic Editor: Fengqiang Sun

Copyright © 2014 Anju K. Augustine et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We present third-order optical nonlinear absorption in CdSe quantum dots (QDs) with particle sizes in the range of 4.16–5.25 nm which has been evaluated by the -scan technique. At an excitation irradiance of 0.54 GW/cm2 the CdSe QDs exhibit reverse saturation indicating a clear nonlinear behavior. Nonlinearity increases with particle size in CdSe QDs within the range of our investigations which in turn depends on the optical band gap. The optical limiting threshold of the QDs varies from 0.35 GW/cm2 to 0.57 GW/cm2 which makes CdSe QDs a promising candidate for reverse-saturable absorption based devices at high laser intensities such as optical limiters.