Fig. 4:

Temporal mode of a laser beam illustrated schematically. (4a): Continuous wave (CW). (4b): Switched, chopped or gated CW beam, producing a series of square waveforms. These are not, strictly speaking, “pulses”, because a pulsed beam has a pulsewidth of 1 ms or less. (4c): A train of laser pulses with pulsewidths of from ms tons, with a long interpulse interval, is seen by the tissue the average power of the peak power and zero watts during the long interpulse interval. This known as quasi-CW. (4d): Quasi-CW can also be delivered as so-called “superpulsed” or “ultrapulsed” modes as illustrated. The ultrapulse dmode is also known as the char-free mode because it produces less charring due to the very short pulsewidths, much less than the thermal relaxation time of the target tissue.