Near-resonant two-photon absorption in luminescent CdTe quantum dots

Khatei, Jayakrishna and Sandeep, Suchand CS and Philip, Reji and Rao, Koteswara KSR (2012) Near-resonant two-photon absorption in luminescent CdTe quantum dots. In: Applied Physics Letters, 100 (8).

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Abstract

We report the nonlinear optical absorption studies in two differently sized water-soluble cadmium telluride quantum dot (QD) samples, exhibiting first excitonic absorption peaks at 493 nm and 551 nm, respectively. An optical limiting behavior is observed for near-resonant excitation at 532 nm using nanosecond laser pulses, originating from the effective two-photon absorption (TPA) mechanism. The effective TPA coefficient (beta(eff)) is measured to be in the range of 10(-12) m/W. This is one order of magnitude higher than the TPA coefficient (beta) reported for off-resonant excitation. At this excitation wavelength, the smaller QD shows a relatively weaker photoluminescence and stronger nonlinear absorption. (C) 2012 American Institute of Physics. [doi:10.1063/1.3687695]

Item Type:	Journal Article
Publication:	Applied Physics Letters
Publisher:	American Institute of Physics
Additional Information:	Copyright of this article belongs to American Institute of Physics.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	28 Mar 2012 06:02
Last Modified:	28 Mar 2012 06:02
URI:	http://eprints.iisc.ac.in/id/eprint/44091

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