Transfer of continuous-relief diffractive structures into diamond by use of inductively coupled plasma dry etching

The transfer of continuous-relief diffractive structures from resist into d iamond by use of direct-write electron-beam lithography followed by dry etc hing in an inductively coupled plasma is demonstrated, The gases used for t he diamond etching are O-2 and Ar. The chemical-vapor-deposited diamond sub strate is of optical quality. Our results show that the transfer process ge nerates fairly smooth etched structures. Blazed gratings with periods of 45 mum and Fresnel lenses have been manufactured. The blazed gratings have be en optically evaluated with a femtosecond laser operating at 400 nm. The di ffraction efficiency was 68% in the first order, with a theoretical value o f 100%. We intend to investigate the transfer process further and then to f abricate diffractive and refractive elements for use with Nd:YAG high-power lasers. (C) 2001 Optical Society of America.