Radiant power incident per unit area upon a surface, expressed in watts-per-centimeter-squared (W·cm^-2).  Symbol: E

Exposure to radiant energy, such as heat, X-rays, or light; the product of irradiance and time.

A unit of energy. 1 joule = 1 Newton • meter; 1 watt • second. Joule is a measurement frequently given for laser output in pulsed operation.

In welding, the deep-penetration holes, which fill quickly with molten metal, that can be made in a few milliseconds by laser.