# ECE/PH 482/582 Fall 2009 Problem Set #5

```ECE/PH 482/582 Fall 2009 Problem Set #5
Due: Wednesday, November 18, 2009 in class
1. Kuhn: Problem 4.14 on ABCD matrix development
2. An argon-ion laser produces a TEMoo Gaussian beam of wavelength 488 nm and has a minimum beam waist
at the output mirror of wo = 0.5 mm. Design a single-lens optical system for focusing the light to a spot of
diameter 100 μm with the lens placed 4 m from the output mirror. [Don’t need to do a full ABCD matrix
approach although you can if you want. What we need is the diameter of lens you would choose and its focal
length.]
3. Consider the ring laser cavity shown in the diagram below.
a) Show an equivalent-lens waveguide for this cavity and identify a unit cell starting just after the lens and
proceeding counterclockwise around the triangle.
b) What is the transmission matrix for this unit cell? (Demonstrate that you have the component matrices in
proper order.)
c) What are the values of d/f that make this a stable cavity?
1
d
d
f
3
2
d/2
d/2
```