The Role of the Pulsed Duration of the Er:YAG 2940 nm Laser on the Dynamics of the Cavitation Bubbles and the Disruption of Microvessels

In this work, two distinct red seaweed agar-based phantom tissue models were employed. In the first model, a single layer was made using 100[Formula: see text]mL of distilled water and 2[Formula: see text]g of agar powder. This model offered a reference point for analyzing the implications of laser radiation without accounting for additional scattering effects. The second model was more complex and had two layers: a scattering layer with 4.8[Formula: see text]g of phospholipids and 100[Formula: see text]mL of emulsion. The experiment used two different pulse lengths: 5[Formula: see text]ns and 90[Formula: see text]fs. These parameters allowed the study to evaluate the effects of different pulse durations on laser-induced bubble dynamics. The results showed that bubble formation in the tissue models was strongly influenced by fluence and pulse duration. Both transient and persistent bubble structures were observed under different irradiation conditions. In each model, the study determined a certain fluence threshold at which bubbles start to form. Remarkably, this threshold increased when scattering was included in the tissue model, suggesting that higher energy levels were needed for scattered light to have the same effects as nonscattering scenarios. Shorter pulses tend to produce more regulated and potentially less damaging interactions with tissue, whereas longer pulse durations may result in more widespread thermal impacts. These findings suggest that by modifying laser parameters such as fluence and pulse duration, physicians might be able to minimize the negative consequences of heat damage or inadvertent vascular disruption.