VHOE Relationships
From HoloWiki  A Holography FAQ
Key  
a = input angle in air  b = output angle in air  a_{n} = input angle in medium 
b_{n} = output angle in medium  f_{0} = spatial frequency = 1/d  λ = wavelength 
n = index of refraction  Δn = index modulation  D.E. = diffraction efficiency 
φ = The half angle  d = grating period  T = thickness of medium 
ρ = regime factor  Q = quality factor  B = fringe tilt angle 
0, +1, 1, +2, 2 = diffraction orders possible  f = focal length  f# = f number 
Grating equation, transmission 
f_{0}λ = sin a + sin b 
D.E. ~ sin^{2} [Δn T / (λ cos φ)] < 99.9% 
Plane grating, slanted fringes, +3 order is TIR, Δn is asymmetric  

Grating equation, reflection 
Uniform tilted reflector, also has weak transmission grating at surface.

Last modified on 9/29/97