Nanodiamonds by laser filamentation in ethanol

An ultrafast laser (λ=1030 nm, ~160 fs) was used to synthesize nanodiamonds directly from ethanol liquid (sans target) through the process of laser filamentation. The laser parameters (such as energy, repetition rate, irradiation time) for nanodiamond synthesis were optimized and characterized with their UV-VIS absorbance, optical emission spectra, Raman, and TEM (transmission electron microscopy) analysis. TEM analysis showed the synthesized nanodiamonds were 2-5 nm size with little or no aggregation and had visible lattice fringes of 2.07 A corresponding to diamond (111). Methods of doping the nanodiamonds with nitrogen or other species during laser synthesis will also be presented.