With the aim to reduce surface reflections and to increase the diffraction efficiency we have investigated the superposition of subwavelength phase gratings onto blazed phase gratings. Using direct write electron-beam lithography bare blazed gratings and blazed gratings carrying subwavelength gratings were fabricated and their optical performances compared. For TE-polarization the subwavelength carrying gratings showed a maximum diffraction efficiency of 90.6%, whereas the corresponding maximum value for the bare grating was 86.3%. The experiment was simulated using rigorous diffraction theory.
|Number of pages||5|
|Journal||Doktorsavhandlingar vid Chalmers Tekniska Hogskola|
|Publication status||Published - 1999|