Confinement-mediated optical properties of ZnO nanorods: Experimental and theoretical investigations

We studied the optical confinement effect of ZnO nanorods and its consequent effect on the optical properties of ZnO nanorods. By solving the Maxwell equations using the three-dimensional, finite difference time-domain method, we investigated the spatial intensity distribution inside and outside the ZnO nanorod. As results of numerical simulations, we found that a strong confinement of optical field exists within the nanorod. In the short-pulse-excited photoluminescence (PL) spectra, the PL enhancement and the spectral narrowing are ascribed to the amplified spontaneous emission caused by coupling the optical confinement effect of ZnO nanorods with the high-intensity excitation.