Three-dimensional laser writing in diamond bulk

Laser fabrication of micrometer-scale graphitic structures in the bulk of monocrystalline CVD diamond was investigated. Ultra-short (1 ps) pulses of Ti:sapphire laser were tightly focused inside the sample. Initiation of graphitization in the focal volume and propagation of graphitization front towards the laser beam are considered. Electrical resistivity of the produced graphitic material was measured (3.6–3.9 Ω cm). Problems and strategies of 3D laser writing are discussed paying special attention to graphitization homogeneity, minimization of the wire diameter, control of the structure shape and reduction of the surrounding diamond damage. Laser fabrication of complex microstructures including pillars, plates, hexagonal chain and periodic arrays of straight wires has been demonstrated. ▶ Graphitic structures are produced inside diamond monocrystal by short laser pulses. ▶ Laser pulse energy and speed of focus movement must be optimized. ▶ Minimum diameter of straight and curved graphitic wires reaches 1 micron. ▶ Diamond is cracked around graphitized region with too large cross-section. ▶ Electrical resistivity of the occurred graphitized material is measured.