Recording of transmission phase gratings in glass by ion implantation

Transmission phase gratings of grating constants of 4-12 mum have been desi gned and fabricated in glass via implantation of helium and nitrogen ions o f energies in the 500 keV-1.6 MeV range, through photoresist masks of thick ness of 3.3 mum. Multienergy implantations were applied, too. Phase profile s of the gratings were measured via interference and phase contrast microsc opy and scanning electron microscopy. Quasisinusoidal profiles were obtaine d for the finest gratings. The highest first order diffraction efficiencies were around 20%. Dependence of the efficiencies of the gratings on the ene rgy and dose of the implantation have been determined. (C) 2001 American In stitute of Physics.