In lasers that the wavelength targets water, a shorter pulse duration is ______.

In lasers that target water, a shorter pulse duration is more safe primarily due to the principle of thermal relaxation time. When the pulse duration is brief, the energy deposition occurs in a very short timeframe, allowing the surrounding tissues adequate time to dissipate heat. This minimizes the risk of thermal damage to adjacent structures.

In contrast, longer pulse durations can lead to significant heat accumulation in the targeted area, potentially resulting in damage to the surrounding tissue. This is particularly critical when dealing with water-containing tissues, as they are more susceptible to changes in temperature. A shorter pulse duration effectively reduces the thermal effect and confines the energy to the intended target without affecting nearby areas, enhancing the safety profile of the procedure.