s: 
parameterization 
of 
the 
ray 
trajectory q(s): 
position 
vector 
for 
the 
ray 
trajectory 
at 
s; 
p(s): … See more

Momentum 
changes 
along 
trajectory 
arc 
length 
in 
proportion 
to 
the 
local 
refractive 
index 
gradient These are the “equations of motion,” i.e. they yield the ray trajectories. See more

s: 
parameterization 
of 
the 
ray 
trajectory q(s): 
position 
vector 
for 
the 
ray 
trajectory 
at 
s; 
p(s): 
tangent 
vector 
to 
the 
ray 
trajectory 
at 
s s p(s) q(s+Δs) p(s) p(s+Δs) s ∇n(q) = 
low 
index 
… See more