Multi-photon excitation properties of CdSe quantum dots solutions and optical limiting behavior in infrared range

Optics Express (Impact Factor: 3.49). 11/2007; 15(20):12818-33. DOI: 10.1364/OE.15.012818
Source: PubMed


Multi-photon absorption and excitation properties of CdSe quantum dots in hexane with different dot-sizes have been investigated. The two- and three-photon absorption (2PA and 3PA) coefficients were measured by using ~160-fs laser pulses at wavelengths of ~775-nm and ~1300-nm, respectively. The dependence of one-, two- and three-photon induced fluorescence spectra as well as their double-exponential decay on the dot-sizes was studied. Based on the fluorescence emission spectra and temporal decay constants for a given sample solution excited by one-, two-and three-photon absorption, it can be concluded that the transition pathways for fluorescence emission and decay under one-, two- and three-photon excitation are nearly identical. The optical power limiting capabilities based on 2PA and 3PA mechanisms are demonstrated separately. In addition, a saturation behavior of 3PA at ~1300 nm was observed.

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    • "The former can be further divided into multi-photon absorption (MPA), RSA and free-carrier absorption (FCA). Up to date, numerous inorganic and organic materials, such as phthalocyanines (O'Flaherty et al. 2003; de la Torre et al. 2004), porphyrins (Blau et al. 1985; Senge et al. 2007), organic dyes (He et al. 1995; He et al. 2008), metal nanoclusters (Sun et al. 1999; Wang et al. 2009), quantum dots (He et al. 2007), etc. have been found to possess OL response. Carbon-related nanomaterials are actually a main branch in the field of OL materials (Chen et al. 2007; Wang et al. 2009). "

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