Directionality in laser fabrication of 3D graphitic microwires in diamond

摘要

Graphitic wires embedded beneath the surface of single crystal diamond are promising for a variety of applications. Through a combination of ultrashort (femtosecond) pulsed fabrication, high numerical aperture focusing and adaptive optics, graphitic wires can be written along any 3D path. Here, we demonstrate a non-reciprocal directional dependence to the graphitization process: the features are distinct when the fabrication direction is reversed. The non-reciprocal effects are significantly determined by the laser power, the fabrication speed, the light polarization and pulse front tilt. The influences of these factors are studied.