Authors:	I. Moreels, Z. Hens, P. Kockaert, J. Loicq, D. Van Thourhout
Title:	Spectroscopy of the nonlinear refractive index of colloidal PbSe nanocrystals
Format:	International Journal
Publication date:	11/2006
Journal/Conference/Book:	Applied Physics Letters
Volume(Issue):	89(19) p.193106 (3 pages)
DOI:	10.1063/1.2385658
Citations:	36 (Dimensions.ai - last update: 9/3/2025) 19 (OpenCitations - last update: 3/5/2025) Look up on Google Scholar
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Abstract

A spectroscopic study of the optical nonlinearity of PbSe colloidal solutions was performed with the
Z-scan technique at wavelength intervals of 1200–1350 and 1540–1750 nm. While nonlinear
absorption remains below the detection threshold, the third order nonlinear refractive index n2
shows clear resonances, somewhat blueshifted relative to the exciton transitions in the absorbance
spectrum. The occurrence of thermal effects is ruled out by time-resolved measurements. At
1.55
m, measured
resonant n2 values exceed typical bulk semiconductor values by two orders of
magnitude. At high optical intensity, the refractive index change saturates, indicating that statefilling
lies at the origin of the observed effect.