What is a Continuous Wave?

Most common lasers generate a continuous, uninterrupted beam of light. These are called continuous wave lasers. They often have stable power and intensity. Some lasers are pulsed such that the light, and thus the energy, is only present for a short amount of time, such as nano- or femtosecond durations (10^-9 and 10^-15 s, respectively). Because the energy is delivered in such a short amount of time, pulsed lasers have high peak powers and intensities.