Development of a SEM-based low-energy in-line electron holography microscope for individual particle imaging

•A SEM-based low-energy in-line holography has been under development to image light elemental materials, biological specimens with high contrast and low-dose owing to high scattering cross-sections in the low-energy range.•Reconstructed holographic images show superior contrast and resolution and stability of holographic imaging than those of SEM and STEM.•Owing to the operational functionalities of SEM-based microscope, fast mode switching between SEM, STEM and holography mode is possible. A new SEM-based in-line electron holography microscope has been under development. The microscope utilizes conventional SEM and BF-STEM functionality to allow for rapid searching of the specimen of interest, seamless interchange between SEM, BF-STEM and holographic imaging modes, and makes use of coherent low-energy in-line electron holography to obtain low-dose, high-contrast images of light element materials. We report here an overview of the instrumentation and first experimental results on gold nano-particles and carbon nano-fibers for system performance tests. Reconstructed images obtained from the holographic imaging mode of the new microscope show substantial image contrast and resolution compared to those acquired by SEM and BF-STEM modes, demonstrating the feasibility of high-contrast imaging via low-energy in-line electron holography. The prospect of utilizing the new microscope to image purified biological specimens at the individual particle level is discussed and electron optical issues and challenges to further improve resolution and contrast are considered.