What is the diameter of the beam?

The beam diameter is measuring the size of the beam or other electromagnetic radiation such as laser. It is a diameter on any line that is perpendicular and intersects the beam axes and is double the length of the beam radius. At the circular beam, its length is defined as the length of the segment of the line that passes through the center of the beam and has its endpoints on the opposite edges of the beam. If the beam is elliptical, its diameter can be specified as a length of either the main or small ellipse axis. If the beam does not have a circular symmetry, it is referred to the beam width instead. There are therefore a number of ways to define the diameter of the beam. The beam diameter measurement is carried out using a device called a laser beam profter. The point on the beam, where the diameter of the beam is the narrowest is called the beam beam.

The beam diameter is an important attribute of lasers. Rays with a larger diameter suffer from less divergence of the beam, which is measurement of that JAK, the beam light spreads from the waist of the beam. Thus, low divergence rays have a higher beam quality, measurement of how firmly focused a laser beam remains when it travels. The optical intensity of the beam is the amount of optical energy that the beam provides per unit of the area at the target, so that the laser with low beam divergence will have more optical intensity than a beam with the same optical energy, but higher beam divergence. This is important for many laser applications such as cutting, drilling and remote welding in industry and laser microscopy in biological science.

There is a compromise between the quality of the laser beam and the size of the laser, because the laser with a smaller lens has a smaller diameter of the beam and will suffer from greater divergence, all other things are the same. Reducing the laser, which is often desirable because of comfort and cost, while maintaining high beam quality requires improvements in other parts of design. This can be done using optical components of higher quality, OptimalIzed design and resonator alignment and using laser gain medium, which is less prone to disruption of thermal effects such as thermal lens.