Optics 2026

The performance and robustness of laser material processing is governed by the ablation threshold, defined as the minimum laser energy required to initiate material removal. Conventionally, the ablation threshold is regarded as a well-defined quantity determined solely by intrinsic material properties and laser parameters such as wavelength, pulse du ration, and repetition rate. Under fixed irradiation conditions, this threshold is assumed to be immutable, limiting control over laser–matter interaction. In this work, we challenge this long-standing assumption by demonstrating active control of ablation threshold in dielectrics, semiconductors, and metals using asymmetric optical vortex beams carrying orbital angular momentum (OAM). By shifting the phase singularity of the beam and changing its handedness, we tailor the spatial distribution of optical phase and intensity, thereby modulating multiphoton absorption during laser irradiation. This enabled us to achieve up to 60% variation in the ablation threshold under both single-pulse and multi-pulse irradiation. This approach enables dynamic control of laser–matter interactions, offering new opportunities for mitigating damage in high-energy optical systems and precision fabrication of microstructures with engineered morphologies and enhanced control.

I started my PhD at the University of Ottawa, where I have been studying the fundamental physics of laser–material interactions. My first research project investigated laser-induced phase transformations in silicon during femtosecond laser ablation. In collaboration with other research groups, I have also worked on the fabrication of optical waveguides in fused silica and laser inscription of fiber Bragg gratings. My current research investigates how the helicity of optical vortex beams influences the laser ablation threshold of materials, providing new insights into light–matter interactions and laser processing.