Control of Organic Crystal Shape by Femtosecond Laser Ablation

Control of organic crystal shape is crucial for various scientific and industrial fields, while it is still very challenging even with systematic optimization of environmental parameters such as temperature and concentration. Here we report an innovative approach for spatiotemporal control of organic crystal growth by directly modifying local crystal structures via femtosecond laser ablation. We found that a crystal face that is locally ablated only with a single laser pulse shows enhanced growth without the loss of crystal quality. The underlying mechanism can be explained by the generation of energetically favorable crystal growth mode (spiral growth mode), which is a fundamental growth mode for various organic crystals. We demonstrated that various crystal shapes can be achieved by femtosecond laser ablation. The fine-tuned, spatiotemporal cue given by femtosecond laser ablation will provide a facile means to obtain organic crystals with desired shape.