Nano-optical spin electronics based on near-field optical microscopic technique

基于近场光学显微技术的纳米光学自旋电子学

基本信息

批准号：
14076206
负责人：
SAIKI Toshiharu
金额：
$ 12.61万
依托单位：
Keio Univesity
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

项目摘要

As well as the control of interband-polarization coherence, the storage and manipulation of spin coherence is of great importance in spintronics. The quantum confinement of electrons is advantageous for spintronics in terms of the control of spin behavior through the optimization of spin lifetime and g-factor. For local injection, control, and detection of spin-polarized electrons in individual quantum structures, optical spin manipulation with the near-field light source is needed.We have established a near-field scanning optical microscope (NSOM) system to measure and manipulate the spin state of a single quantum dot (QD) with a high spatiotemporal resolution under a magnetic field up to 5T. The spatial resolution as high as 30-50 nm enabled us to visualize wave functions of quantum-confined excitons.Owing to the high spatial resolution of our NSOM, the shape of the QD is clearly visualized. From magneto-PL spectroscopy of a single QD, a diamagnetic shift of the exciton emission was observed. Referring to the theoretical value we estimate the size of the QD from a diamagnetic coefficient, which is determined by the Bohr radius of excitons confined in QDs. The result was in good agreement with that obtained by the real-space NSOM mapping.We also built a near-field optical microscope for polarization spectroscopy in the reflection configuration. Polarization properties of good quality and stability as well as high optical throughput allows high-sensitive magneto-optical spectroscopy with high spatial resolution. Kerr-rotation imaging of magnetic domains in garnet thin films and depolarization microscopy of a phase-change material with a spatial resolution of 30 nm are demonstrated.

除了控制带间极化连贯性外，自旋连贯性的存储和操纵在旋转中非常重要。通过优化自旋寿命和G因子的控制，电子对旋转行为的控制对于自旋行为的控制是有利的。为了在单个量子结构中局部注入，控制和检测自旋极化电子，需要使用近场光源进行光学自旋操作。我们已经建立了一个近场扫描光学显微镜（NSOM）系统，以在高端子端口（QD）下的单个量子点（QD）的旋转状态，以高端分辨率的上升为单位的旋转状态。空间分辨率高达30-50 nm，使我们能够可视化量子限制的激子的波函数。由于我们的NSOM的高空间分辨率，QD的形状清楚地看到了。从单个QD的磁磁PPL光谱中，观察到激子发射的磁管变化。指的是理论值，我们从dimagnetic系数中估算了QD的大小，该系数由限制在QD中的激子的BOHR半径确定。结果与真实空间NSOM映射获得的结果非常吻合。我们还在反射配置中构建了一个近场光学显微镜，用于极化光谱。高质量和稳定性以及高光学吞吐量的极化特性允许具有高空间分辨率的高敏磁光谱。证明了石榴石薄膜中磁域的KERR旋转成像和空间分辨率为30 nm的相变材料的去极化显微镜。