Femtosecond Laser-Material Interactions

Laser ablation processes dominate technologies used in the fabrication and characterization of materials. Fabrication examples include  displays, smartphones, circuits all the way to automotives, and textile industries. Characterization of  samples include practically any application imaginable, including batteries, solar photovoltaics, biology, environmental samples and nuclear security. Over the past decade the emergence of lasers in a number of applications dictates revisiting the fundamental processes. All applications are driven by fundamentals.

The fundamental processes of the interaction of lasers directly determine processes in laser micro/nano-fabrication, direct laser writing, cutting, laser 3D printing, deposition. They also determine the plasma properties which directly affect all different types of laser ablation spectroscopy, which are the technologies that help us identify the chemical makeup of any material system, which is directly related to its properties. Examples include quality control in advanced manufacturing, low level impurities in materials, the distribution of elements in complex materials such as Li-ion batteries, all of which determine the performance. Control of these properties is critical in developing the next-generation of improved laser processes for impactful applications in every day life.

The interaction of pulsed laser beams with matter involve complex processes that span over several timescales that range from the femtosecond to the millisecond regime depending on the laser source. At high enough pulsed laser energies, the process of laser ablation takes place. Laser ablation refers to the material removal from a material surface (attogram to microgram scale) accompanied by the formation of of a laser induced plasma.

Our group studies the behavior of materials under femtosecond (10^-15) and nanosecond (10^-9) laser ablation and the properties of the expanding laser induced plasma. These are the key parameters that determine the behavior of laser micromachining and in laser spectroscopy, and indentifying the processes that will improve their quality and performance.