High-efficiency transmission gratings buried in a fused-SiO2 glass plate.
Binary gratings were fabricated with high first-order diffraction efficiency by conventional electron-beam drawing and subsequent inductive coupled-plasma dry etching upon the surfaces of SiO2 glass plates. The gratings were covered with a thin SiO2 film by plasma-enhanced chemical-vapor deposition without the grooves' being filled in. The buried gratings exhibited first-order diffraction efficiencies of 84% for transverse-electric and 87% for transverse-magnetic polarized light at a wavelength of 1.55 microm when the period and the depth were 1.5 and 2.8 microm, respectively.
Nishii
Junji
J
Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan. junji.nishii@aist.go.jp
Kintaka
Kenji
K
Nakazawa
Tatsuhiro
T