Which term best describes the effect of pulse duration on tissue affected by a laser?

The term that best describes the effect of pulse duration on tissue affected by a laser is "thermal relaxation." This concept refers to the time it takes for the tissue to dissipate the heat generated by the laser during and after exposure. When a laser beam interacts with biological tissue, it induces a rapid increase in temperature, and the ability of the tissue to cool down is crucial for determining the extent of thermal damage.

If the pulse duration is shorter than the thermal relaxation time of the tissue, the tissue may not have sufficient time to dissipate the heat before the next pulse, leading to increased thermal effects. Conversely, if the pulse duration exceeds the thermal relaxation time, the tissue has the opportunity to cool down, potentially reducing the extent of thermal damage.

Understanding thermal relaxation helps practitioners optimize laser parameters for effective treatment while minimizing collateral damage to surrounding tissues. This is particularly important in medical and aesthetic laser applications, where precision and safety are paramount.