Department of Scitec, University of Applied Sciences, Carl-Zeiss-Promenade 2, 07745 Jena, Germany.
Institute of Experimental Physics, Technische Universität Bergakademie Freiberg, Leipziger Str. 23, 09596 Freiberg, Germany.
Rev Sci Instrum. 2023 Feb 1;94(2):023703. doi: 10.1063/5.0131144.
A laser scanning microscope for measuring 3D pyroelectric distributions inside thin vinylidene fluoride-trifluoroethylene copolymer films using the Laser Intensity Modulation Method was developed. The setup consists of a laser unit, a laser driver, an xyz-stepper motor unit, a transimpedance amplifier, and a lock-in amplifier. The focus lens at the laser unit is fixed by magnetic levitation and can correct a defocusing of the system or a tilt of the sample surface. It has been demonstrated in different samples that the system has a lateral resolution of 1 μm for measuring the topological surface structure or the pyroelectric distributions. The self-developed laser driver and transimpedance amplifier combined with a fast lock-in amplifier are able to measure small pyroelectric currents and their variation inside a pyroelectric sample in the range of some 1 pA. The maximum measure frequency of 4 MHz and the fast lock-in make it possible to measure the 3D pyroelectric distributions with high resolution. A 3D scan of 30 different layers with depths of 100 nm-5 μm inside the sample and 100 × 100 points in the xy-direction per layer is performed in 3 days.
我们开发了一种激光扫描显微镜，用于使用激光强度调制法测量薄的偏氟乙烯-三氟乙烯共聚物薄膜内部的三维热释电分布。该装置由激光单元、激光驱动器、xyz 步进电机单元、跨阻放大器和锁相放大器组成。激光单元的聚焦透镜通过磁悬浮固定，可以校正系统的离焦或样品表面的倾斜。在不同的样品中已经证明，该系统具有 1 μm 的横向分辨率，可用于测量拓扑表面结构或热释电分布。我们自行开发的激光驱动器和跨阻放大器与快速锁相放大器相结合，能够测量热释电样品内部小至 1 pA 的热释电电流及其变化。4 MHz 的最大测量频率和快速锁相使得以高分辨率测量三维热释电分布成为可能。在 3 天内，对样品内部 30 个不同深度为 100nm-5μm 的层进行了 30 次三维扫描，每个层的 xy 方向有 100×100 个点。
