Critical repair of an ultrafast laser system for research on semiconductor materials

在半导体电子学和光子学中，电子对光的响应是其功能的基础。例如，在太阳能电池中，光的吸收产生电荷，该电荷导致电流并因此产生电能。在光学器件中，当光与半导体中的电子强烈相互作用时，光被活性介质操纵。在我们的研究小组中，我们非常详细地研究了半导体中光和电子之间的相互作用，特别是在所谓的有机半导体中，其中分子基序是固态结构的构建块，而不是传统半导体中的原子。为了研究真实的最快的电子过程，我们使用非常短的激光脉冲（短至10 fs，即百万分之一秒的十亿分之一），该激光脉冲来自每毫秒间隔产生一个这样的短脉冲的激光系统。然后，所产生的激光脉冲串与感兴趣的样品相互作用，然后在该事件之后探测其响应作为时间的函数。例如，分析作为时间的函数的由样品重新发射的光的强度。这些测量揭示了有关材料基本光学性质的丰富信息，这对于支持它们在光电子学和光子学中的大量应用中的功能至关重要。

In semiconductor electronics and photonics, the response of electrons to light is what underpins their function. For example, in solar cells, absorption of light produces charges that result in electrical current and thus produce electrical energy. In optical devices, light is manipulated by the active medium when it interacts strongly with electrons in the semiconductor. In our research group, we study in great detail the interactions between light and electrons in semiconductors, particularly in so-called organic semiconductors, in which molecular motifs are the building blocks of solid-state architectures instead of atoms as in traditional semiconductors. In order to study the fastest electronic processes in real time, we use very short laser pulses (as short as 10 fs, that is 10 billionth of a millionth of a second) derived from a laser system producing one such short pulse every millisecond interval. The resulting train of laser pulses then interacts with the sample of interest, and its response is then probed as a function of time following that event. For example, the intensity of light re-emitted by the sample is analyzed as a function of time. These measurements unravel a wealth of information on the basic optical properties of the material, which is essential to underpin their function in a plethora of applications in optoelectronics and photonics.