Rowan Jones

Major: Physics

Mentors: Sam Bonkowsky, Chenhao Jin 

Laser Micromachining of Magnon Interfaces

Magnons, the quanta of spin-wave excitations in magnets, provide a promising platform for next-generation wave-based computing. CrSBr, an antiferromagnetic van der Waals semiconductor, is excellent for studying magnon propagation because its strong magnon exciton coupling enables convenient optical readout. Furthermore, modulating CrSBr thickness controls the magnon velocity, making thickness-engineered CrSBr interfaces a promising route towards magnonic devices. In CrSBr, such interfaces have been previously achieved via lithography and dry-etching, a process that is costly to iterate, time-consuming, and requires exposure to multiple chemicals. Here, we develop an automated 44 laser-micromachining platform for directly cutting exfoliated CrSBr flakes. The system integrates precision motorized positioning, a pulsed supercontinuum laser, microscope objectives, a nitrogen blower and a custom control software to enable programmable fabrication of micron-scale structures. Using this system we have cut various CrSBr flakes into a variety of designs, including flat interfaces and lenses. We tuned laser fluence, repetition rate, filter configuration, cut speed, laser focus and analyzed their effects using atomic force microscopy to minimize cut width and maximize sidewall steepness. By replacing a multi-step cleanroom process with direct in-lab patterning, this approach promises to substantially simplify the fabrication workflow and enables faster device iteration in CrSBr.