High-performance and highly stable 0.3-nm-full-width-at-half-maximum interference optical filters

• Published in: Applied optics (2004) Vol. 33; no. 16; p. 3513
• Main Authors: Yanagimachi, T, Oguri, H, Nayyer, J, Ishihara, S, Minowa, J
• Format: Journal Article
• Language: English
• Published: United States 01.06.1994
• ISSN: 1559-128X
• DOI: 10.1364/AO.33.003513

Fabrication of very-narrow-bandpass optical tunable filters [(0.3 nm full width at half-maximum) (FWHM)] is reported. To improve the film densities, the O(2) ion-assisted deposition-method is used in the fabrication. In the succession of high- and low-refractive-index layers, the commonly used TiO(2) material is replaced by Ta(2)O(5), which suits the ion-assisted fabrication technique. The relative thicknesses of the filter multilayer structure of 1/2/1 are modified to 0.998/2.007/0.998, which reduces the shift difference in the central wavelengths with regard to the p and s polarizations when the filter is tilted. These improvements enabled fabrication of 0.3-nm-FWHM optical tunable filters with improved stability characteristics.