Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands.
J Chem Phys. 2013 Jul 7;139(1):014303. doi: 10.1063/1.4811181.
We conduct a theoretical study of the bistable optical response of a nanoparticle heterodimer comprised of a closely spaced semiconductor quantum dot and a metal nanoparticle. The bistable nature of the response results from the interplay between the quantum dot's optical nonlinearity and its self-action (feedback) originating from the presence of the metal nanoparticle. The feedback is governed by a complex valued coupling parameter G = G(R) + iG(I). We calculate the bistability phase diagram within the system's parameter space: spanned by G(R), G(I), and Δ, the latter being the detuning between the driving frequency and the transition frequency of the quantum dot. Additionally, switching times from the lower stable branch to the upper one (and vice versa) are calculated as a function of the intensity of the driving field. The conditions for bistability to occur can be realized, for example, for a heterodimer comprised of a closely spaced CdSe (or CdSe/ZnSe) quantum dot and a gold nanosphere.
我们对由紧密间隔的半导体量子点和金属纳米颗粒组成的纳米粒子异质二聚体的双稳光学响应进行了理论研究。响应的双稳性质源于量子点的光学非线性与其自作用（反馈）之间的相互作用，而自作用则源于金属纳米颗粒的存在。反馈由复数值耦合参数 G = G(R) + iG(I) 控制。我们在系统的参数空间内计算了双稳相图：该空间由 G(R)、G(I)和 Δ 来定义，后者是驱动频率与量子点跃迁频率之间的失谐。此外，还计算了从下稳定分支到上稳定分支（反之亦然）的切换时间作为驱动场强度的函数。例如，对于由紧密间隔的 CdSe（或 CdSe/ZnSe）量子点和金纳米球组成的异质二聚体，可以实现双稳发生的条件。
