At Picosecond laser pulse width, the generated photomechanical stress target pigment particle,making its volume expansion instantaneously and resulting in breakup of target into micro-particles, which is much easier for phagocytes to clear. Q-switch laser has pulse width of 5ns or more, its photomechanical stress is not efficient compared to picosecond laser, it creates large particles, and with long pulse width, scattering energy goes toward surrounding tissue,resulting in risks of thermal damage.
Therefore, Picosecond laser provide a more effective and more safe treatment than Q-switch laser.
