Handbook of Biomedical Optics

Optics: Basic Physics 43

we construct a spherical interface of radius R that focuses the

emitted light to point P, regardless of where it hits the interface?

What should R be? Point P is embedded in a medium of index

of refraction n

2

; we are considering the shape of the interface

between media 1 and 2. Consider n

2

> n

1

, so that the rays from S

will be refracted “inwards.”

In Figure 3.13, Point C is the center of the sphere of radius R.

e distance between the “object” point, S, and the interface is s

o

,

and the distance between the “image” point, P, and the interface

is s

i

. e angles that the incident and reected rays make with

respect to t