Ultraviolet photoluminescence in Gd-doped silica and phosphosilicate fibers
Optical fiber lasers operating in the near infrared (IR) and visible spectral regions have relied on the spectroscopic properties of rare earth ions such as Yb 3+ , Er 3+ , Tm 3+ , Nd 3+ and Sm 3+ . Here, we investigate Gd 3+ doping in phosphosilicate and pure silica fibers using solution doping and sol-gel techniques respectively for potential applications in the ultraviolet (UV). Photoluminescence spectra for optical fiber bundles and fiber preforms were recorded and compared. Emissions at
... ed. Emissions at 312 nm (phosphosilicate) and 314 nm (pure silica) were observed when pumping to the Gd 3+ 6 DJ, 6 IJ, and 6 PJ=5/2, 3/2 energy levels. Oxygen deficient center was observed in solution doping sample with a wide absorption band centered at around 248 nm not affecting pumping to 6 IJ states. Ultraviolet (UV) light sources have found numerous applications in medical science and engineering, such as disinfection, water purification, food manufacturing, UV curing and lithography 1-4 , as short wavelengths have relatively high photon energy and provide high resolution. Currently, UV sources consist mostly of gas lasers 5 , lamps or diodes 1 , or rely on nonlinear optical processes, such as third/fourth harmonic generation or optical parametric oscillators (OPOs) 6-7 . Fiberized laser sources could be an attractive alternative to conventional UV sources. Fiber based light sources exhibit excellent beam quality, extraordinary brightness, small detrimental thermal effects and high temporal stability. Fiber lasers operating in the near infrared and visible mostly rely on the spectroscopic properties of rare earth ions 8 . High-power Yb 3+ -doped a Author to whom correspondence should be addressed. Electronic mail: firstname.lastname@example.org.