We look at how saturation causes hole burning in a spectral line, and measurement techniques such as lamb-dip spectroscopy and intermodulated fluorescence that can take advantage of this for doppler-free measurements.

We look at basic methods of emission spectroscopy including laser induced fluorescence, resonant enhanced multi-photon emission (REMPI), intermodulated fluorescence and stimulated emission pumping.

WE look at basic techniques of absorption spectroscopy including direct detection, frequency modulation, intracavity absorption and cavity ringdown spectroscopy.

We look at how the natural lifetime of an energy level produces a Lorentzian line profile and how the natural linewidth can be broadened by Doppler broadening, pressure broadening, transit time broadening and saturation broadening.

We look at how interferometers can be used to measure wanelength.