Kloth P, Thias T, Bunjes O, von der Haar J, Wenderoth M
IV. Physical Institute-Solids and Nanostructures, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
Rev Sci Instrum. 2016 Dec;87(12):123702. doi: 10.1063/1.4971189.
We present a combination of pulsed optical excitation and scanning tunneling microscopy with a highly flexible pulse generation method. A high frequency arbitrary wave generator drives a gigahertz electro-optical modulator, which processes a continuous-wave laser beam of a low-noise laser diode into the desired wave shape. For pump-probe excitation we generate optical pulse series in an all-electronic way. Thereby we can easily adapt parameters like pulse amplitude, width, or repetition cycle to the demands of the experiment. This setup is used to study different dynamic processes at the GaAs(110) surface. Separating thermally induced effects from electrically induced effects allows us to quantify the thermal contribution of the optical excitation in STM experiments. Time-resolved decay spectra of the photo-generated electron-hole pairs demonstrate the nanoscale spatial resolution.
我们展示了一种将脉冲光激发与扫描隧道显微镜相结合的方法，该方法具有高度灵活的脉冲产生方式。高频任意波形发生器驱动千兆赫兹电光调制器，该调制器将低噪声激光二极管的连续激光束处理成所需的波形。对于泵浦-探测激发，我们以全电子方式产生光脉冲序列。由此，我们可以轻松地根据实验需求调整诸如脉冲幅度、宽度或重复周期等参数。此装置用于研究GaAs(110)表面的不同动态过程。将热诱导效应与电诱导效应分离，使我们能够在STM实验中量化光激发的热贡献。光生电子-空穴对的时间分辨衰减光谱证明了纳米级空间分辨率。
