## 4 Discussion  
In this study, we investigated the thermo-optical and optomechanical effects of short-pulse laser irradiation on a layered skin model, aligning our methodology with previous research for robust comparisons. Our analysis focused on determining the heat-affected region resulting from laser radiation across various laser variables, including wavelength, radiation intensity, laser beam size, and exposure time. To capture the intricate dynamics, we conducted numerical simulations employing a finite element model within the COMSOL Multiphysics program. This choice was motivated by the program's capabilities in studying thermal diffusion, coupled with static and kinetic mechanical analyses. The accuracy of our model was rigorously verified by examining temperature distributions, mechanical stresses, and deformations. Notably, our results underscored the pivotal roles of exposure time and laser intensity in achieving the requisite treatment temperature. Furthermore, we observed a balanced interaction between intensity and exposure time in attaining the optimal temperature. These findings align closely with the observations of [PERSON] et al. [30]. Our analysis of short laser pulses demonstrated their ability to deliver high energy to target sites efficiently, producing a well-defined heat-affected area. We delved into the thermal and mechanical effects over time intervals ranging from 30 to 600 s, focusing particularly on the thermomechanical effect, which emerged as predominant in laser-tissue reactions. The study's parametric analysis encompassed the frequency, beam size, intensity, and exposure time of pulse radiation, elucidating the photomechanical interaction. The coupling feature in COMSOL Multiphysics facilitated simulations, revealing that equivalent stress peaked around 2 MPa, gradually diminishing with distance from the irradiation point. These findings align closely with the observations of [PERSON] et al. [30]  
Figure 11: Box-Behnken optimization results (**a**): Response surface \(S_{\text{max}}\) as a function of beam intensity I and exposure time T. (**b**): Response surface \(T_{\text{max}}\) as a function of beam intensity I and exposure time T. (**c**): The effect of changing the values of beam intensity I on changing the values of temperature \(T_{\text{max}}\) and stress \(S_{\text{max}}\). (**d**): The effect of changing the values of exposure time T on changing the values of temperature \(T_{\text{max}}\) and stress \(S_{\text{max}}\). and underscore the significance of temperature-stress relationships, especially in the axial direction. Utilizing a second-order polynomial model, we quantitatively evaluated the effects of laser intensity, beam size, wavelength, and exposure time on temperature prediction. Our modeling efforts revealed that a 532 nm laser with an intensity of 1 W/mm\({}^{2}\), a beam size of 3 mm, and an exposure time of 309 s could produce a maximum temperature of 43 \({}^{\circ}\)C.  
Our study highlights the need for further experimental investigations to elucidate variable blood perfusion rates and assess thermal damage, particularly in tumor tissues with high blood perfusion rates. We suggest employing established thermal damage equations, such as the first-order Arrhenius equation [35], modified Arrhenius equation [36], or temperature-dependent time-delay equation [37], to refine predictions and accommodate tissue-specific variations. Moreover, our investigation could be expanded by employing controlled micro/nano-scale periodic surface structures in conjunction with femtosecond pulsed lasers to enhance tumor ablation [38]. Looking ahead, our thermomechanical model can be extended to analyze tumor cell necrosis using quantitative models under imaging guidance and track drug delivery employing shorter laser pulses. Incorporating thermal damage details and Von [PERSON] stresses from temperature-time history would enhance computational predictions, supporting pre-clinical and clinical assessments.