Tailoring light–matter–spin interactions in colloidal hetero-nanostructures
Tailoring light–matter–spin interactions in colloidal hetero-nanostructures
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DOI：
10.1038/nature09150
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发表时间：
2010-07
期刊：
影响因子：
64.8
通讯作者：
Jiatao Zhang;Yun Tang;Kwan Lee;Ouyang Min
中科院分区：
文献类型：
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作者：
Jiatao Zhang;Yun Tang;Kwan Lee;Ouyang Min
光和物质之间的相互作用是许多基本过程和各种应用的基础。利用光与物质的相互作用原理可以使固态器件在新的物理原理下工作：例如，交流电磁场。光学斯塔克效应（OSE）使半导体中自旋的相干量子控制方案成为可能，具有实现基于自旋量子比特的量子器件的潜力。然而，随着半导体尺寸的减小，光-物质耦合通常会减弱，从而限制了纳米级的应用。最近的实验已经证明了纳米级光-物质相互作用的显著增强，尽管需要高精细度腔，最终阻止了器件的缩小和集成。在这里，我们报告说，一个相当大的OSE可以实现在大量的能量失谐在无腔的胶体金属-半导体核-壳异质纳米结构，其中金属表面等离子体被调谐到共振光谱与半导体激子跃迁。我们进一步证明，这种共振增强的OSE表现出偏振依赖性，并提供了一个可行的机制，在胶体纳米结构内的相干超快自旋操纵。等离子体激元-激子共振性质还使得能够通过调谐等离子体激元共振强度和频率来定制OSE和自旋操纵。这些结果打开了一个途径，通过等离子激元共振耦合在一个明智的工程纳米结构定制光-物质-自旋相互作用，并提供了一个基础，为未来的应用在纳米级的量子信息处理。更一般地说，具有共振增强的光-物质相互作用的集成纳米结构应该作为其他新兴领域的测试平台，包括纳米生物光子学和纳米能源。
The interplay between light and matter is the basis of many fundamental processes and various applications. Harnessing light–matter interactions in principle allows operation of solid state devices under new physical principles: for example, the a.c. optical Stark effect (OSE) has enabled coherent quantum control schemes of spins in semiconductors, with the potential for realizing quantum devices based on spin qubits,,,. However, as the dimension of semiconductors is reduced, light–matter coupling is typically weakened, thus limiting applications at the nanoscale. Recent experiments have demonstrated significant enhancement of nanoscale light–matter interactions, albeit with the need for a high-finesse cavity,, ultimately preventing device down-scaling and integration. Here we report that a sizable OSE can be achieved at substantial energy detuning in a cavity-free colloidal metal–semiconductor core–shell hetero-nanostructure, in which the metal surface plasmon is tuned to resonate spectrally with a semiconductor exciton transition. We further demonstrate that this resonantly enhanced OSE exhibits polarization dependence and provides a viable mechanism for coherent ultrafast spin manipulation within colloidal nanostructures. The plasmon–exciton resonant nature further enables tailoring of both OSE and spin manipulation by tuning plasmon resonance intensity and frequency. These results open a pathway for tailoring light–matter–spin interactions through plasmon–exciton resonant coupling in a judiciously engineered nanostructure, and offer a basis for future applications in quantum information processing at the nanoscale. More generally, integrated nanostructures with resonantly enhanced light–matter interactions should serve as a test bed for other emerging fields, including nano-biophotonics and nano-energy,.