Ooe Kousuke, Seki Takehito, Nogami Mitsuru, Ikuhara Yuichi, Shibata Naoya
Institute of Engineering Innovation, School of Engineering, The University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-0032, Japan.
Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1, Mutsuno, Atsuta, Nagoya, Aichi 456-8587, Japan.
Microscopy (Oxf). 2025 Mar 31;74(2):98-106. doi: 10.1093/jmicro/dfae051.
Optimum bright-field scanning transmission electron microscopy (OBF STEM) is a recently developed low-dose imaging technique that uses a segmented or pixelated detector. While we previously reported that OBF STEM with a segmented detector has a higher efficiency than conventional STEM techniques such as annular bright field (ABF), the imaging efficiency is expected to be further improved by using a pixelated detector. In this study, we adopted a pixelated detector for the OBF technique and investigated the imaging characteristics. Because OBF imaging is based on the thick weak phase object approximation (tWPOA), a non-zero crystalline sample thickness is considered in addition to the conventional WPOA, where the pixelated OBF method can be regarded as the theoretical extension of single side band (SSB) ptychography. Thus, we compared these two techniques via signal-to-noise ratio transfer functions (SNRTFs), multi-slice image simulations, and experiments, showing how the OBF technique can improve dose efficiency from the conventional WPOA-based ptychographic imaging.
最佳明场扫描透射电子显微镜（OBF STEM）是一种最近开发的使用分段或像素化探测器的低剂量成像技术。虽然我们之前报道过，配备分段探测器的OBF STEM比传统的STEM技术（如环形明场（ABF））具有更高的效率，但预计使用像素化探测器可进一步提高成像效率。在本研究中，我们将像素化探测器应用于OBF技术并研究了其成像特性。由于OBF成像基于厚弱相位物体近似（tWPOA），除了传统的WPOA外，还考虑了非零晶体样品厚度，其中像素化OBF方法可被视为单边带（SSB）叠层成像的理论扩展。因此，我们通过信噪比传递函数（SNRTFs）、多切片图像模拟和实验对这两种技术进行了比较，展示了OBF技术如何从传统的基于WPOA的叠层成像提高剂量效率。
