Singlet

n O n L n I
n O
n L
n I
R 1   ( mm )
R 2   ( mm )
f   ( mm )
Thickness   ( mm )
R 2 = - R 1

Doublet

n O
n 1 n 2
n I
n 1
n 2
V 1
V 2
R 1   ( mm )
R 2   ( mm )
R 3   ( mm )
R 2 = - R 1
d 1   ( mm )
d 2   ( mm )
f 1   ( mm )
f 2   ( mm )