The primary advantage of picosecond lasers lies in their ultrashort pulse durations, typically ranging from 300 to 700 picoseconds. However, shorter is not always better—there exists a practical “lower limit” for pulse width. While extremely short pulses enhance optoacoustic mechanical effects, they may also cause molecular bond disruption, obscure clinical endpoints, and reduce the laser’s selective photothermolysis between normal skin and pigmented lesions, thereby compromising both precision and safety.

For example, the Picoway system (Candela‑Syneron) employs a pulse duration of 450 picoseconds. Clinical experience suggests that 400 to 500 picoseconds represents a reasonable lower limit for picosecond laser pulse widths, offering an optimal balance between fragmentation efficiency and safety margins.

When the 1064nm picosecond beam passes through a KTP crystal, the resulting 532nm wavelength exhibits a shortened pulse duration—approximately 300 picoseconds, about 100 picoseconds less than its 1064nm counterpart. This means that the 532nm wavelength delivers stronger mechanical effects when treating superficial pigmentation, with more rapid endpoint responses.

Additionally, the “honeycomb” skin rejuvenation function (utilizing 1064nm or 755nm) has gained significant clinical attention. This technique employs a microlens array to refocus the laser energy into a “stamped” fractional pattern, significantly increasing local fluence at each spot. This induces controlled microcavitation injuries within the dermis, triggering the skin’s natural repair mechanisms and achieving comprehensive skin brightening, rejuvenation, and regenerative remodeling effects.