418 



WRIGHT— POLARIZED LIGHT IN THE 



This equation shows that the higher the refractive index the more 

 light is reflected. The relative intensities for a series of refractive 

 indices are listed in Table 2. 



Equation (23) reduces for k = o to tan (r — A^)=o; in other 

 words, there is no change in phase on reflection. Vertically incident 

 plane-polarized light is reflected as plane-polarized light without 

 change of phase and with no change in azimuth of polarization plane. 

 (Equation (27) for n^^Ur, and Kj^ = k2 = o.) 



Birefracting Media. — For a birefracting transparent medium 

 (ki=:/co^o) ; equation (28) reduces to 



Irs / «i — I Y / ^^2 + I Y 

 Irp~\ni+ I ) \n2 - I J 



4(W2 — Wi) 



I — 



+ 



4(«2 - wi) 



(31) 



(Wi+ I)(W2 - I) («i + I)2(W2 - 1)2 



The third term of the last expression is negligible for weakly bi- 

 refracting substances. The change in intensity ratio with change in 

 least refractive index n^ and with birefringence (wo — n^) is shown 

 in Table 3 and presented graphically in Fig 2. 



TABLE 3. 



In this table are given the relative intensities of the two components, 

 normal and parallel to the plane of incidence, of light waves reflected from 

 a transparent birefracting crystal surface whose low refractive index is «i 

 and whose birefringence is ;;- — n^. Thus for a crystal plate, whose least 

 refractive index is 1.8 and whose birefringence is 0.040, the ratio of the inten- 

 sities of the two reflected components is 0.932. 



