In this paper, we describe an experiment for two-photon excitation in laser-cooled <sup>87</sup>Rb using an optical nanofiber. A brief description of the multilevel atom scheme is followed by experimental results on two-photon absorption and observation of Autler-Townes splitting in cold atoms. These experiments use powers several orders of magnitude lower than those used in free space experiments.
Zinc Oxide nanoparticles and nanorods have been synthesized at an optimum temperature of 60°C using aqueous
solution of zinc acetate and potassium hydroxide in methanol. Particle and rod like structures were obtained by merely
varying the relative concentration of the reagents. A variety of techniques like UV-Vis absorption spectroscopy, X-ray
diffraction (XRD), photoluminescence, Fourier transform infrared (FTIR) spectroscopy and scanning electron
microscopy (SEM) were used to carry out structural and spectroscopic characterizations. FTIR confirms the preparation
of zinc oxide. XRD shows the formation of well crystalline nature and wurtzite structure of prepared zinc oxide samples.
Grain sizes were also calculated using XRD data and found to be in 11-15nm range for all preparations. Presence of one-dimensional
structures in the rod samples were confirmed by SEM images. Blue shift of the absorption peaks were found
due to quantum confinement of excitons. Capping action of polyvinyl pyrrolidone (PVP) was also studied. Use of PVP
leads to the decrement in aspect ratio of rods but provides spherical shaped nanostructures. Enhancement of UV-emission
intensity with suppression of green emission intensity was observed by the use of PVP during preparation.