How does a continuous-wave laser differ from a pulsed laser?

The primary difference between these two types of lasers lies in how they deliver their output energy over time.

• Continuous-wave lasers: These devices produce an output that remains nominally constant over an interval of seconds or longer. A common example of this steady emission is the beam produced by a laser pointer.1
• Pulsed lasers: These systems concentrate their output energy into brief, high-power bursts. They can be designed to fire either single pulses or a series of pulses at regular intervals. By compressing these pulses into extremely short durations—sometimes as brief as 5 femtoseconds—these lasers can "freeze" rapid events, such as stages in chemical reactions.1

While a continuous-wave laser provides a steady stream of light, a pulsed laser can achieve extremely high instantaneous power at the peak of a very short pulse, with some experimental systems reaching peak powers exceeding ${10}^{15}$ watts.1