Foell Charles A, Schelew Ellen, Qiao Haijun, Abel Keith A, Hughes Stephen, van Veggel Frank C J M, Young Jeff F
Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.
Opt Express. 2012 May 7;20(10):10453-69. doi: 10.1364/OE.20.010453.
We report coupling of the excitonic photon emission from photoexcited PbSe colloidal quantum dots (QDs) into an optical circuit that was fabricated in a silicon-on-insulator wafer using a CMOS-compatible process. The coupling between excitons and sub-μm sized silicon channel waveguides was mediated by a photonic crystal microcavity. The intensity of the coupled light saturates rapidly with the optical excitation power. The saturation behaviour was quantitatively studied using an isolated photonic crystal cavity with PbSe QDs site-selectively located at the cavity mode antinode position. Saturation occurs when a few μW of continuous wave HeNe pump power excites the QDs with a Gaussian spot size of 2 μm. By comparing the results with a master equation analysis that rigorously accounts for the complex dielectric environment of the QD excitons, the saturation is attributed to ground state depletion due to a non-radiative exciton decay channel with a trap state lifetime ~ 3 μs.
我们报道了将光激发的PbSe胶体量子点（QDs）的激子光子发射耦合到一个采用CMOS兼容工艺在绝缘体上硅晶圆中制造的光学电路中。激子与亚微米尺寸的硅沟道波导之间的耦合由光子晶体微腔介导。耦合光的强度随光激发功率迅速饱和。使用一个孤立的光子晶体腔对饱和行为进行了定量研究，该腔中PbSe量子点被位点选择性地置于腔模波腹位置。当几微瓦的连续波氦氖泵浦功率以2微米的高斯光斑尺寸激发量子点时，就会出现饱和。通过将结果与严格考虑量子点激子复杂介电环境的主方程分析进行比较，饱和归因于具有约3微秒陷阱态寿命的非辐射激子衰变通道导致的基态耗尽。
