Exclusive and Accelerated\nβ‑to‑α\nPolymorphic Transition in Glycine Crystals Induced by Femtosecond\nLaser Pulses

The precise control of polymorphic transitions is of\nparamount\nimportance in materials science and pharmaceuticals. Here, we report\nthe exclusive and accelerated β-to-α polymorphic transition\nin glycine crystals induced by tightly focused, high-repetition-rate\nfemtosecond laser pulses. Laser irradiation triggers the transition\nat the etched area, likely due to molecular reorientation during local\nmelting. Notably, the transition velocity under laser irradiation\nis several thousand times faster than that observed in spontaneous\ntransitions. Furthermore, we observed that both laser fluence and\nthe crystal’s microenvironment (e.g., dry vs wet) significantly\ninfluence the transition dynamics. This study not only provides insights\ninto the mechanism of laser-induced polymorphic transitions but also\noffers a potential tool for precise polymorph control, which may find\nbroad applications in various materials.