What determines the depth of penetration in laser treatments?

The depth of penetration in laser treatments is primarily influenced by the wavelength and spot size of the laser. Different wavelengths correspond to varying levels of absorption by different tissues, which dictates how deeply the laser energy can penetrate. For instance, longer wavelengths may penetrate deeper into the skin because they are less absorbed by the superficial layers, whereas shorter wavelengths may be absorbed more quickly.

Additionally, the spot size, or the area over which the laser energy is delivered, also plays a crucial role. A smaller spot size concentrates energy in a smaller area, which can lead to higher energy density and can affect the thermal effects within the targeted tissue. Conversely, a larger spot size distributes the energy over a wider area, potentially resulting in shallower penetration.

Together, these factors directly determine how effectively the laser treatment reaches the desired depth within the skin or other tissues, which is crucial for achieving the intended therapeutic outcomes.