Title: "CVD-Diamond Waveguides for High-Gradient Wakefield Acceleration: Synthesis, Laser-Machining, and THz Field Performance" Abstract: This paper presents advancements in chemical vapor deposition (CVD) diamond as a novel dielectric material for next-generation particle accelerator components. We detail the fabrication of cylindrical and planar diamond structures via microwave plasma-assisted CVD, laser micromachining, and surface modification for use in dielectric-loaded accelerating (DLA) systems. Raman spectroscopy confirms high sp³ character and crystalline integrity, while wakefield experiments conducted at the Brookhaven and Argonne accelerator facilities demonstrate sustained electric fields exceeding 300 MV/m and transient gradients approaching 1 GV/m without dielectric breakdown. The integration of single-crystal and polycrystalline CVD diamond into tunable THz structures highlights the material's exceptional thermal conductivity, low loss tangent, and surface stability under extreme RF conditions. These results underscore CVD diamond’s transformative potential in lab-grown material applications beyond traditional industrial and gem uses, positioning it as a cornerstone for future high-energy physics and compact accelerator designs.