THIN-FILM RETARDATION PLATES OF SILICA GLASS FABRICATED BY OBLIQUE DEPOSITIONS

We developed thin film retardation plates of silica glass which work w ith normally incident lights at a wavelength as short as 300 nm. By de positing silica from an oblique direction (70 degrees from the substra te surface-normal) onto substrates, unique microscopic columnar struct ures were obtained. The columns of approximately 20 nm in diameter wer e inclined to the deposition direction which cause birefringence. Alth ough obliquely deposited thin films often become opaque because of coa lescence of the columns enhanced by absorbing moisture after the depos ition processes, the opacity was suppressed using stacked structures o f obliquely deposited and normally deposited layers.