Abstract
We have developed a new CLEM (Correlative Light Electron Microscope) with a merged system combining a light microscope module and a commercial desktop electron microscope (TEMIC-EM100). A 10X objective lens with long working distance is positioned in between the BSED (Backscatter Electron Detector) and the sample stage of a scanning electron microscope (SEM). A 45 mirror mounted on a home-built objective nose piece guides the light from the objective lens to the sample and vice versa. The system is designed in such a way that all components of the light microscope except the objective lens and the reflection mirror are positioned outside the vacuum. With the new system development, the SEM objective lens and the light objective lens have a common axis and focal plane, allowing high-resolution optical microscopy and scanning electron microscopy on the same area of a sample by simply moving and repositioning the light microscope module, thus leading to correlative imaging. We demonstrate the use of our light microscope module as a kind of “preview option” for SEM. The light microscope gives visibility to the copper mesh (grid size : 5 μm*5 μm), individual grid can be clearly identified in the image. Based on the image, a region can be selected for SEM inspection at high magnification. Our future work is to extend a fluorescence analysis function in the module to study living cells. We have developed a fluorescence microscope module on the original low magnification “preview” module. A 350 W Xenon lamp light source with collimator lens is used to illuminate polystyrene particle sample(Fluoro-Max R400 ; particle size 400 nm), and an emission of orange 612 nm fluorescence image is taken by the 100X objective lens.