REFLECTED-LIGHT MICROSCOPY 



153 



fore be applied to any objective or any magnifying power. On the 

 other hand, the mirror M is substituted for a semi-reflective plate 

 thus allowing full aperture of the pupil. 



Multi-wave layouts 



The multi-beam interferometer is eminently suitable for investi- 

 gating surface micro-structures. The procedure is to dress the surface 

 so that it becomes highly reflective and to lay on it a metallized 





Fig. 4.33. "Multimi" Johansson interference microscope. 



optically-flat surface. The numerous inter-surface reflections taking 

 place evince a system of fine fringes. The process of this phenomenon 

 is similar to the one described in Chapter III, § 10. These fine fringes 

 are tantamount to topographical contour lines and enable detection 

 of very minute surface flatness imperfections in the object. Figure 4.32 

 shows a microscope constructed on this basic principle by Bausch 

 and Lomb. Reichert, VEB Zeiss, Johansson (Fig. 4.33), Hilger and 

 Watt (Fig. 4.34) have also built multi-wave interference micro- 

 scopes. 



