Ultrafast photoinduced enhancement of nonlinear optical response in 15-atom gold clusters on indium tin oxide conducting film

Kumar, Sunil and Shibu, ES and Pradeep, T and Sood, AK (2013) Ultrafast photoinduced enhancement of nonlinear optical response in 15-atom gold clusters on indium tin oxide conducting film. In: Optics Express, 21 (7). pp. 8483-8492.

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Abstract

We show that the third order optical nonlinearity of 15-atom gold clusters is significantly enhanced when in contact with indium tin oxide (ITO) conducting film. Open and close aperture z-scan experiments together with non-degenerate pump-probe differential transmission experiments were done using 80 fs laser pulses centered at 395 nm and 790 nm on gold clusters encased inside cyclodextrin cavities. We show that two photon absorption coefficient is enhanced by an order of magnitude as compared to that when the clusters are on pristine glass plate. The enhancement for the nonlinear optical refraction coefficient is similar to 3 times. The photo-induced excited state absorption using pump-probe experiments at pump wavelength of 395 nm and probe at 790 nm also show an enhancement by an order of magnitude. These results attributed to the excited state energy transfer in the coupled gold cluster-ITO system are different from the enhancement seen so far in charge donor-acceptor complexes and nanoparticle-conjugate polymer composites.

Item Type:	Journal Article
Publication:	Optics Express
Publisher:	Optical Society of America
Additional Information:	Copyright of this article belongs to Optical Society of America.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	30 May 2013 11:23
Last Modified:	30 May 2013 11:23
URI:	http://eprints.iisc.ac.in/id/eprint/46601

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