104 



PROGRESS IN MICROSCOPY 



Jamin's interferometer, inserted between the condenser C and the 

 microscope objective O^. The polarizers are on each side of the plates 

 at 5*1 and iPo. The system, as devised by Lebedeff. is only suitable 

 for wide front-lenses and, therefore of low maanification. 



\ 



^«. 



QC 



="? 



3, 



Fig. 3.10. Lebedeff interference microscope. 



6. THEORETICAL PRINCIPLE OF POL.\RIZING INTERFERENCE 



MICROSCOPES 



In all polarizing interference microscopes the image is duplicated. 

 In Fig. 3.11, the ordinary ray originated by Si, emerging in the di- 

 rection (I) passes through the object A as does the extraordinary ray 



h'- 



/ 



-^A -^ 



/ 



t '(I) 

 L -(2) 



Fig. 3.11. Image duplication in a polarization interferometer. 



originated by another ray S. emerging in the direction (2). Therefore, 

 when looking at A through the system, the two images (1) and (2) 

 are seen, which are ofl'set by the distance d. To such shift must be 

 added another: the longitudinal one towards the rays, because the 



