Scanning electron microscopic (SEM) measurement
During most of the research and development sample visualization is necessary, but sometimes the resolution of human eyes or CCD cameras are not suitable. Due to the diffraction of the visible light optical microscopes have a maximum magnification, which is around 5000 times in case of modern digital optical microscopes. Higher magnifications can be reach by change the wavelength of the probe particle (e.g. from photon to accelerated electron). The imaging method of scanning electron microscopes (SEM) and optical microscopes is very similar, but the maximum magnification of SEM is much higher. Objects with 1-2 nm size can be seen in SEM images.