This paper presents the morphological and microstructural response of Jalore Pink Granite (JPG) under two laser-processing modes of a continuous-wave CO 2 laser: raster-mode scanning and manually controlled burst-mode pulsing. In scanning, laser power (70–90 W) and scan speed (50–150 mm/s) influenced material removal (up to 0.014 g), scan diameter, and morphological features. Higher power and lower speed promoted thermal accumulation, producing denser striations with thickness increasing from 0.072 to 0.097 mm and spacing decreasing to 0.033 mm. Associated surface effects included swelling, glazing, soot deposition, and ridge breakdown, with spatial variability highlighting the anisotropic thermo-physical behavior of JPG. In manual burst-mode pulsing (laser power: 10–90 W; burst repetitions: 10–100), the thermally influenced zone exhibited distinct morphologies. In general, four distinct thermal zones were observed, while in some cases, shattered glass, oil spillage, or smoky protrusions were observed. Quantitative analysis, performed to understand the diverse response of the thermally influenced zone, revealed a nonlinear correlation between the thermally influenced zone and the energy density, where a 3-degree cubic model performed best, with R 2 of 0.6242. Microstructural characterization confirmed localized melting, pore development, and granular degradation in irradiated regions (FESEM), along with persistent quartz phases and alterations in the diffraction pattern (XRD). These findings present laser irradiation as an effective method for controlled micro-structuring of granitoid rocks, emphasizing the importance of selecting the laser-processing mode and parameters, and considering rock anisotropy in governing surface modification during geological engineering applications.
Sinha et al. (2026) studied this question.