MULTI-PHOTON ABSORPTION INDUCED PHOTOLUMINESCENCE IN DOPED SEMICONDUCTOR QUANTUM DOTS AND HETERO-NANOSTRUCTURES

Abstract

MATERIALS WITH HIGH MULTI-PHOTON ABSORPTION CROSS-SECTION ARE OF RECENT INTEREST IN OPTO-ELECTRONIC AND BIOLOGICAL APPLICATIONS SUCH AS OPTICAL LIMITING, THREE-DIMENSIONAL DATA STORAGE, MULTI-PHOTON MICROSCOPY ETC. OWING TO THE PROPERTIES SUCH AS REMARKABLE PHOTO STABILITY, BRIGHTNESS AND SIZE DEPENDENT ABSORPTION AND EMISSION, SEMICONDUCTOR NANOCRYSTALS (NCS) ARE PREFERRED OVER OTHER CONVENTIONAL FLUOROPHORES AS BIO-IMAGING PROBES IN MULTI-PHOTON MICROSCOPY. THE MAJOR IMPEDIMENT TO USE MULTI-PHOTON ABSORPTION IN NCS FOR PRACTICAL APPLICATIONS IS THE REQUIREMENT OF HIGH EXCITATION INTENSITY BECAUSE OF THE LOW ABSORPTION CROSS-SECTION OF NANOCRYSTALS IN NEAR-INFRARED (NIR) WAVELENGTHS. THIS DISSERTATION AIMS AT ENHANCING THE MULTI-PHOTON ABSORPTION CROSS-SECTION OF NANOCRYSTALS IN NIR WAVELENGTHS BY DOPING AND BY FORMING HETERO-NANOSTRUCTURES. SPECIFICALLY, THIS THESIS PRESENTS THE NONLINEAR OPTICAL INVESTIGATIONS OF THE MULTI-PHOTON ABSORPTION INDUCED PHOTOLUMINESCENCE IN MN2+-DOPED ZN