Spectral and nonlinear optical characterization of ZnO nanocomposites

Dyuthi/Manakin Repository

Spectral and nonlinear optical characterization of ZnO nanocomposites

Show simple item record

dc.contributor.author Litty, Mathew Irimpan
dc.contributor.author Radhakrishnan, P
dc.contributor.author V P N Nampoori
dc.date.accessioned 2010-04-28T04:32:32Z
dc.date.available 2010-04-28T04:32:32Z
dc.date.issued 2008-06
dc.identifier.citation Cochin University of Science and Technology en_US
dc.identifier.uri http://dyuthi.cusat.ac.in/jspui/handle/dyuthi/1674
dc.description.abstract The spectral and nonlinear optical characteristics of nano ZnO and its composites are investigated. The fluorescence behaviour of nano colloids of ZnO has been studied as a function of the excitation wavelength and there is a red shift in emission peak with excitation wavelength. Apart from the observation of the reported ultra violet and green emissions, our results reveal that additional blue emissions at 420 nm and 490 nm are developed with increasing particle size. Systematic studies on nano ZnO have indicated the presence of luminescence due to excitonic emissions when excited with 255 nm as well as significant contribution from surface defect states when excited with 325 nm. In the weak confinement regime, the third-order optical susceptibility χ(3) increases with increasing particle size (R) and annealing temperature (T) and a R2 and T2.5 dependence of χ(3) is obtained for nano ZnO. ZnO nanocolloids exhibit induced absorption whereas the self assembled films of ZnO exhibit saturable absorption due to saturation of linear absorption of ZnO defect states and electronic effects. ZnO nanocomposites exhibit negative nonlinear index of refraction which can be attributed to two photon absorption followed by weak free carrier absorption. The increase of the third-order nonlinearity in the composites can be attributed to the enhancement of exciton oscillator strength. The nonlinear response of ZnO nanocomposites is wavelength dependent and switching from induced absorption to saturable absorption has been observed at resonant wavelengths. Such a change-over is related to the interplay of plasmon/exciton band bleach and optical limiting mechanisms. This study is important in identifying the spectral range and the composition over which the nonlinear material acts as an optical limiter. ZnO based nanocomposites are potential materials for enhanced and tunable light emission and for the development of nonlinear optical devices with a relatively small optical limiting threshold. en_US
dc.language.iso en en_US
dc.publisher International School of Photonics en_US
dc.subject Nanophotonics en_US
dc.subject Fluorescence spectroscopy of nano colloids of ZnO en_US
dc.subject nonlinear optical properties in nano colloids of ZnO en_US
dc.subject Spectral and NLO characteristics of Self assembled films of ZnO en_US
dc.subject nonlinear optical characteristics of thin films of nano ZnO en_US
dc.subject ZnO nanocomposites en_US
dc.subject Spectral and nonlinear optical characterization en_US
dc.title Spectral and nonlinear optical characterization of ZnO nanocomposites en_US
dc.type Thesis en_US


Files in this item

Files Size Format View Description
Dyuthi-T0546.pdf 2.313Mb PDF View/Open PDF

This item appears in the following Collection(s)

Show simple item record

Search Dyuthi


Advanced Search

Browse

My Account