Observation of a fifth order optical nonlinearity in 29 kDa Au@alkanethiol clusters excited in the visible

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/2248

Title:	Observation of a fifth order optical nonlinearity in 29 kDa Au@alkanethiol clusters excited in the visible
Authors:	Thomas, Jinto Anija, M. Cyriac, Jobin Pradeep, T. Philip, Reji
Issue Date:	25-Feb-2005
Publisher:	Elsevier B.V.
Citation:	Chemical Physics Letters, 2005, Vol.403, p308-313
Abstract:	The absorptive optical nonlinearity in nanoclusters of Au@hexanethiol and Au@dodecanethiol has been investigated. From the mass spectra, each cluster is estimated to contain about 140 atoms of gold. The optical absorption spectra of the clusters show a gradual increase in absorbance towards the UV region, over which an extremely weak surface plasmon resonance (SPR) is superposed. No plasmon bleach effects are seen when the samples are excited with nanosecond laser pulses at 532 nm. Instead, a reduced transmission behavior is observed, which fits to a three-photon absorption mechanism. We propose that this nonlinearity is caused by two-photon induced excited state absorption occurring in the nanoclusters. Femtosecond pump–probe studies show that when excited and probed at 400 nm, the nonlinearity is very fast with a lifetime of less than 2 ps.
Description:	Restricted Access.
URI:	http://hdl.handle.net/2289/2248
ISSN:	0009-2614
Alternative Location:	http://dx.doi.org/10.1016/j.cplett.2005.01.019
Copyright:	2005 Elsevier B.V.
Appears in Collections:	Research Papers (LAMP)

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