The_Cambridge_Handbook_of_Physics_Formulas

8.5 Geometrical optics
169
Prisms (dispersing)
α
δ
θ i
θ t
prism
Transmission
angle
sinθ t =(η 2 −sin 2 θ i ) 1/2 sinα
−sinθ i cosα (8.72)
θ i
θ t
α
η
angle of incidence
angle of transmission
apex angle
refractive index
Deviation δ = θ i +θ t −α (8.73) δ angle of deviation
Minimum
deviation
condition
Refractive
index
Angular
dispersion a
a At minimum deviation.
sinθ i =sinθ t = ηsin α 2
η = sin[(δ m +α)/2]
sin(α/2)
D = dδ
dλ = 2sin(α/2) dη
cos[(δ m +α)/2] dλ
(8.74)
(8.75) δ m minimum deviation
D dispersion
(8.76)
λ wavelength
Optical fibres
L
θ m
cladding, η c