Optical emission spectroscopy for diagnosis of diamond growth and etching processes in microwave plasma V.Yu. Yurov, E.V. Bushuev, A.P. Bolshakov, I.A. Antonova, V.G. Ralchenko and V.I. Konov EPJ Web Conf., 149 (2017) 02013 Published online: 04 August 2017 DOI: 10.1051/epjconf/201714902013