A type of optical lens assembly designed to provide a flat field at the image plane of the scanning system. It is commonly used in laser marking, engraving, and cutting systems in conjunction with a laser beam expander and galvanometer.

The angular width of a beam. With respect to a conical beam of light, it is the vertex angle of the cone. The beam width is a measure of the rate of divergence or convergence of a light beam.

The calculated distance between two exactly opposed points on a beam at a chosen fraction of peak power (typically 1/e2). It is also defined as the diameter of a circular aperture that will pass a specified percentage (usually 90%) of the total beam energy.

The increase in cross-sectional area of a propagating beam of light that is not perfectly collimated.

The maximum amount of laser power per area that a surface can withstand before it is damaged. For pulsed lasers, typically measured in mJ/cm2; for continuous wave lasers, typically in W/cm2. This measurement is very important for mirrors or any other optical component used in conjunction with laser products.

See also Power Density, Laser