Blue light has a wavelength of 0. 47 um Resolution max -0.2 um(200 nm) Cannot go beyond this even with better optics Solution? Use illumination of shorter wavelength Antone de broglie(1924) Theory of wave nature of electrons Hermann Busch(1924) axial magnetic fields refract electrons Electron optics
Blue light has a wavelength of 0.47 um Resolution max - 0.2 um (200 nm) Cannot go beyond this even with better optics. Solution? Use illumination of shorter wavelength Antone de Broglie (1924) Theory of wave nature of electrons Hermann Busch (1924) axial magnetic fields refract electrons Electron optics
·1935- Max Knoll 1938-First scanning elect demonstrates the theory of the microscope produced by voi scanning electro microscope Ardenne von ardenne Knoll and ruska 1986 Nobel Prize winners 1939-Ruska and von borries working for Siemens produce the first commercially available em
•1935 - Max Knoll demonstrates the theory of the scanning electron microscope Knoll and Ruska 1986 Nobel Prize winners von Ardenne 1939 - Ruska and von Borries, working for Siemens produce the first commercially available EM 1938 - First scanning electron microscope produced by von Ardenne
1939-First EM built in north america by James Hillier and albert Rebus at the University of Toronto Dr. Rebus DLa/李
•1939 - First EM built in North America by James Hillier and Albert Prebus at the University of Toronto Dr. Prebus Dr. Ladd
LM TEM SEM Ilumination source Condenser Condense Lens ens Objective Final Lens "【∑ Projection Lens Specimen Light vs Electron Microscope Eye Phosphorescent Screen
Light vs Electron Microscope
光学显微镜的分辨率 由于光波的波动性,使 得由透镜各部分折射到 像平面上的像点及其周 物面 围区域的光波发生相互 干涉作用,产生衍射效 物镜 应。一个理想的物点, 19% 经过透镜成像时,由于 衍射效应,在像平面上 形成的不再是一个像点, 像面 而是一个具有一定尺寸 Airy斑 的中央亮斑和周围明暗 相间的圆环所构成的 Airy斑。如图5-1所示。 图5-1两个电光源成像时形成的Airy斑 (a)Airy斑:(b)两个Airy斑靠近到刚好能分得开的临界距离时强度的叠加
光学显微镜的分辨率 • 由于光波的波动性，使 得由透镜各部分折射到 像平面上的像点及其周 围区域的光波发生相互 干涉作用，产生衍射效 应。一个理想的物点， 经过透镜成像时，由于 衍射效应，在像平面上 形成的不再是一个像点， 而是一个具有一定尺寸 的中央亮斑和周围明暗 相间的圆环所构成的 Airy斑。如图5-1所示