Lasers come in many configurations with wavelengths from UV to far infrared, and each of these has its uses. They also can range in power from fractions of milliWatts to thousands of Watts, nanoJoules to kiloJoules. On the low end of the power ranges, applications can be for fiber optic telecommunication, laser scanning, or laser printing. Middle ranges, from a few hundred mW to tens of Watts, are used for surgery, eye repair, marking, LIDAR and range finding, plastic welding, and many other precision applications. At the high end, industrial welding and cutting, and military applications are predominant. Each of these requires different configurations of the laser beam, and profiling can help ensure that the laser matches the application's needs.
There are several different types of profiling instruments, CCD camera arrays, pyroelectric arrays, scanning slits, spinning reflectors, to name a few. The simplest to understand is the CCD camera, such as the Spiricon SP620. Combined with some attenuation optics, the CCD is placed in the beam path and a picture of the beam is captured. Beam profiling software, coupled to the CCD, provides an analysis of the beam profile. From CCD data it is possible to determine the size of the beam, the distribution of the power/energy in the beam, and, in general, whether the laser is performing as expected.
The silicon CCD is limited to the wavelength range from ~200 to ~1100 nm (UV to near infrared). Although this covers a lot of laser applications, there are wavelengths outside this range. The CCD sensor is very sensitive and delicate, which means that for even the low power lasers, substantial attenuation of the beam is required to avoid saturating or even damaging the array. For this reason, there is always the potential for the addition of error and distortions to the beam profile from these optics. It is also generally impossible to measure tightly focused laser beams with a CCD, because the attenuation optics require a fairly long beam path.