I am reading the book Fundamentals of Photonics. I try to solve problems at the end of chapter 1, but I got stuck on two problems.
- Tiny glass ball are often used as lenses to couple light into and out of optical fibers. The fiber end is located at a distance $f$ from the sphere. For a sphere of radius $a=1$mm and refractive index $n=1.8$, determine $f$ such that a ray parallel to the optical axis at a distance $y=0.7$mm is focused onto the fiber, as illustrated in the picture.
Could you help me?