Fluorine doped silica glass fiber for deep ultraviolet light

Optical fibers for the deep ultraviolet region were developed using fluorine doped silica glasses called ‘modified fused silica’. Optimizing the fiber drawing conditions improved the transmission of the fiber in the deep UV region. The transmittance of the fiber at 193 nm reached more than 65% per 1 m long (65% m−1) without reflection loss. Significant absorption bands from defects were not observed throughout the wavelengths of the deep UV–visible–infrared region. Hydrogen-impregnation into the fibers suppressed the degradation of the transmission induced by irradiating with an ArF excimer laser. Transmission in the DUV region and resistance to laser irradiation were drastically improved compared to high OH silica fibers. Dipping the fibers into a hydrofluoric acid solution automatically prepared fibers with a sharp-pointed edge that were suitable for optical microprobes in scanning near-field optical microscopes.