INFRA-RED AND ULTRA-VIOLET MICROSCOPY 



233 



In 1950, D. S. Grey described several objectives for ultra-violet 

 applications. Numerical apertures range from 0-4 to 10. Figure 9.7 

 shows schematically one of these objectives. The N.A. is 10 and 



Fig. 9.6. Grey and Lee reflecting objective I «sinM = 1,1 



sinWf, 



sinw 



= 0-26 



Fig. 9.7. Grey reflecting objective (wsinw = 1 



sin Wo 



= 0-30 



sin» i 



the occlusion ratio 030; the convex mirror consists of an aluminized 

 portion of the convex surface of a lens. 



Nomarski and Bernstein devised an objective of N.A. nsinu = 090, 

 magnifying power x 100 and spherical aberration-corrected in the 



