What is the outcome if the pulse width is less than or equal to the thermal relaxation time?

When the pulse width of a laser used for hair removal is less than or equal to the thermal relaxation time, it essentially means that the energy delivered by the laser can effectively be absorbed by the hair follicle without excessive heat affecting the surrounding tissue. The thermal relaxation time is the period it takes for the skin to cool after heating; by keeping the pulse width within this timeframe, the energy can target the hair follicle precisely.

In this scenario, since the energy is concentrated on the hair follicle, it can lead to effectively destroying the follicle without damaging the surrounding skin. This results in optimal hair removal outcomes, thereby achieving the desired effect of perfect hair removal. The treatment can be performed safely and more comfortably for the client, as there is a reduced risk of collateral damage and discomfort.

This understanding illustrates the importance of having a precise balance between the pulse width of the laser and the thermal relaxation time to maximize the efficacy of hair removal treatments.