Calculations for Focusing Gaussian Beams

A Gaussian beam is the most basic type of laser beam, and can be represented by the Gaussian beam equation, which represents one solution to the wave equation. In this chapter we shall examine the Gaussian beam equations and derive equations which will allow us to solve laser beam focusing problems. We will also discuss the M-squared factor, which can be used to calculate the focused spot size of an actual laser beam, whose quality is slightly inferior to that of an ideal Gaussian beam.