Nonlinear Optical Switching and Enhanced Nonlinear Optical Response of Au鈥揅dSe Heteronanostructures

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• 作者：V. Sreeramulu ; Krishna Kanta Haldar ; Amitava Patra ; D. Narayana Rao
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：December 26, 2014
• 年：2014
• 卷：118
• 期：51
• 页码：30333-30341
• 全文大小：509K
• ISSN：1932-7455

文摘

The metal鈥搒emiconductor heterostructures have recently emerged as a new class of functional materials for their potential applications due to plasmon-exciton interactions. Here, we demonstrate the nonlinear optical switching and enhanced nonlinear optical response of Au鈥揅dSe heterostructures. The nonlinear optical properties of CdSe quantum dots and Au鈥揅dSe heteronanostructures are investigated by using a Z-scan technique at 532 nm picosecond laser pulses, and 800 nm femtosecond laser pulses. Interestingly, we observe switching behavior from saturable absorption (SA) to reverse saturable absorption (RSA) with increasing laser intensity. The effective two-photon absorption cross section (蟽_eff) of Au鈥揅dSe heteronanostructures is greatly enhanced which is attributed to charge transfer between CdSe and Au nanoparticles. The nonlinear refraction changes its sign from positive to negative nonlinearity at higher intensities for Au鈥揅dSe heterostructures. Third order nonlinear optical susceptibility is being measured by using the DFWM technique at 532 nm. Similar switching behavior is observed in Au鈥揅dSe heteronanostructures at nonresonant excitations (800 nm), where a CdSe quantum dot shows reverse saturable absorption behavior attributed to the two-photon absorption. The optical switching behavior of these heterostructures could play a potential role in photonics and optoelectronic applications.