ABSTRACT
This chapter considers the optical device called the etalon and how to use it to make actual linewidth measurements of real laser beams. It examines how to use optical components to create a beam collimator, expander, or reducer to correct the diverging beam. Some lasers use a technique called modelocking, which uses active optical elements within the laser cavity to limit the time, and sometimes wavelength, that a beam can be propagating within it. One main characteristic of any laser that every laser scientist and engineer must know and truly understand is the amount of output energy, power, and irradiance the device supplies. Every laser application requires a certain type of output and in order to implement safety protocols properly the output must be truly understood. A common practice for laser scientists and engineers is to “collimate” a laser beam using a telescope or other dispersive optical element system.
