## 4 Results  
### Analysis of Temperature Distribution  
The two-dimensional temperature distribution for varying laser powers with \(\alpha\) = 0 kJ/kg and \(\alpha\) = 2260 kJ/kg conditions, depicting temperatures exceeding 60 \({}^{\circ}\)C, is illustrated in Figure 4. As the laser power increases under both conditions, there is a corresponding rise in peak temperature and an expansion in the range of temperatures exceeding 60 \({}^{\circ}\)C. However, compared to the scenario without the addition of latent heat (\(\alpha\) = 0 kJ/kg), incorporating the latent heat of water (\(\alpha\)) results in lower peak temperatures and a narrower range of temperatures exceeding 60 \({}^{\circ}\)C. Further insights into temperature distribution are provided in Figure 5, detailing the volumes of temperatures exceeding 60 \({}^{\circ}\)C for each model. Notably, the volume difference is up to 232 times greater in the model with \(\alpha\) = 0 kJ/kg compared to the model with \(\alpha\) = 2260 kJ/kg at a laser power of 10 W.  
The peak temperatures corresponding to different laser powers under both experimental conditions and simulations are depicted in Figure 6. It is assumed that the temperatures measured by the thermocouples represent the tissue temperature, indicating that the tissue does not undergo transformation into a gasified cavity. The experimental results align well with the \(\alpha\) = 0 kJ/kg model, suggesting good agreement. However, it should be noted that tissue melting and vaporization into a gasified cavity occur when the temperature exceeds  
Figure 3: The ex vivo experimental setup for temperature measurement. Figure 2: The schematic diagram of the laser ablation experiment. 600-700 \({}^{\circ}\)C, known as the threshold temperature [29]. Thus, it is imperative for the tissue temperature to remain below this threshold during laser irradiation to prevent gasification. The measured temperature surpasses the threshold temperature, possibly due to the direct absorption of photons by the thermocouples from the laser. Figure 4: The two-dimensional temperature distribution depicting temperatures exceeding 60 \({}^{\circ}\)C under varying laser powers for two distinct conditions. Figure 5: The volume of temperatures exceeding 60 \({}^{\circ}\)C under different laser power settings at t = 10 s for two distinct conditions. Figure 6: The peak temperatures corresponding to different laser powers. This disparity can be attributed to the variability in the positioning of the fiber relative to the thermocouple during the experiment, deviating from the intended fixed configuration. Additionally, the soft texture of pork liver, coupled with its numerous blood vessels, poses a challenge for the accurate placement of the thermocouples at the desired temperature measurement points. The initial experimental temperature point was notably higher than the corresponding simulated results for each irradiated laser power. It is plausible to speculate that the positioning of the first thermocouple is closer to the laser ablation area, increasing the likelihood of absorbing photon energy directly from the laser irradiation. Therefore, any measured temperature exceeding 600-700 \({}^{\circ}\)C is considered invalid experimental data in this study. The temperature distribution is thoroughly analyzed along the axial direction for the two conditions, \(\alpha\) = 0 kJ/kg and \(\alpha\) = 2260 kJ/kg, both theoretically and experimentally, as depicted in Figure 7. The model with \(\alpha\) = 2260 kJ/kg exhibits a better fit with the experimental data compared to the model with \(\alpha\) = 0 kJ/kg. Specifically, for a laser power of 10 W, the maximum deviation is 72.9% at \(z\) = 7 mm, while the minimum deviation is 2.43% at \(z\) = 1 mm. With a laser power of 14 W, the maximum deviation increases to 82% at \(z\) = 7 mm, with a minimum deviation of 10.4% at \(z\) = 1 mm.