An apparatus, method, and system for post-processing a printed graphene ink pattern or other deposition on a substrate. A pulsed UV laser is tunable between various energy densities to selectively modify the printed ink or deposition in electrical or physical properties. In one example, radical improvements in electrical conductivity are achieved. In another example, controlled transformation from essentially 2D printed or deposited graphene to surface topology of 3D nanostructures are achieved. The 3D structures are beneficial in such applications as electrochemical sensors of different types and characteristics. In another example, hydrophobicity of the printed or deposited graphene can be manipulated starting from a hydrophilic to super hydrophobic surface.