Nechay B A, Siegner U, Achermann M, Morier-Genaud F, Schertel A, Keller U
Swiss Federal Institute of Technology Zurich, Institute of Quantum Electronics.
J Microsc. 1999 May-Jun;194(Pt 2-3):329-34. doi: 10.1046/j.1365-2818.1999.00528.x.
We have developed an instrument for optically measuring carrier dynamics in thin-film materials with approximately 150 nm lateral resolution, approximately 250 fs temporal resolution and high sensitivity. This is accomplished by combining an ultrafast pump-probe laser spectroscopic technique with a near-field scanning optical microscope. A diffraction-limited pump and near-field probe configuration is used, with a novel detection system that allows for either two-colour or degenerate pump and probe photon energies, permitting greater measurement flexibility than that reported in earlier published work. The capabilities of this instrument are proven through near-field degenerate pump-probe studies of carrier dynamics in GaAs/AIGaAs single quantum well samples locally patterned by focused ion beam (FIB) implantation. We find that lateral carrier diffusion across the nanometre-scale FIB pattern plays a significant role in the decay of the excited carriers within approximately 1 microm of the implanted stripes, an effect which could not have been resolved with a far-field system.
我们开发了一种仪器，用于光学测量薄膜材料中的载流子动力学，其横向分辨率约为150纳米，时间分辨率约为250飞秒，且灵敏度高。这是通过将超快泵浦-探测激光光谱技术与近场扫描光学显微镜相结合来实现的。采用了衍射极限泵浦和近场探测配置，以及一种新颖的检测系统，该系统允许使用双色或简并泵浦和探测光子能量，比早期发表的工作具有更大的测量灵活性。通过对聚焦离子束（FIB）注入局部图案化的GaAs/AIGaAs单量子阱样品中的载流子动力学进行近场简并泵浦-探测研究，证明了该仪器的性能。我们发现，在植入条纹约1微米范围内，纳米级FIB图案上的横向载流子扩散在激发载流子的衰减中起重要作用，而远场系统无法分辨这种效应。
