
9
GAUSSIAN BEAMS
In Chapter 8, we discussed the Fraunhofer diffraction pattern of Gaussian beams, and we
noted that the Fourier transform of a Gaussian function is also a Gaussian function. We will
see in this chapter that the Gaussian beam is a Gaussian function of transverse distances x
and y at all locations along its axis (z). The Gaussian beam merits its own chapter for several
reasons:
• The output beams of many types of lasers are approximated well by Gaussian functions.
• The Gaussian function is the minimum-uncertainty wave as mentioned in Section 8.1,
which makes it a good limiting case against which to compare other waves.
• The equations