Spectroscopic properties of Sm 3+ -doped phosphate glasses
- PDF / 413,388 Bytes
- 5 Pages / 584.957 x 782.986 pts Page_size
- 52 Downloads / 211 Views
We report on the absorption, static, and transient luminescence spectra of Sm31-doped glasses. The dependences between absorption and emission cross sections as well as between luminescence quantum efficiencies and Sm31 doping concentration are examined. The large stimulated absorption cross section and emission cross section combined with the long fluorescent lifetime make phosphate glasses doped with Sm31 promising material for visible fiber lasers. Moreover, DT(Tx Tg) of these glasses is about 290 °C, which guarantees their thermal stability against crystallization during the fiber drawing process. I. INTRODUCTION
Recent advances in GaN-related semiconductor laser devices have enabled the emergence on the market of light sources in the ultraviolet (UV) to blue wave length region in watt output levels. This in turn promotes the rapid development of visible fiber lasers.1–5 In 2009, Okamoto et al.1 reported visible to near infrared (NIR) tunable fiber laser in a Pr31-doped ZBLAN fluoride glass fiber using a GaN 448-nm multimode laser diode (LD) as a pump source. Then, Fujimoto et al.2,3 also demonstrated yellow and red laser oscillations by using Dy31- and Pr31-doped fluoride glass fibers, respectively. Using a 488-nm argon ion laser as pumping source, Yamashita and Ohisi4 realized a green laser at 542.8 nm from Tb31-doped fluoride glass fiber. The fibers they used were all fluorides, which are usually unstable when exposed to air. Therefore, it is highly desirable to find an alternative material with excellent chemical durability and thermostability. Actually in the 1980s, Farries et al.5 reported a Sm31doped silica optical fiber laser operating at 651 nm using a 488-nm argon ion laser as a pumping source. Due to the severe aggregation of Sm31 when introduced into silica glass, high concentration doping is impractical. This hinders the development of compact of fiber laser devices and the realization of single frequency ultranarrow line width laser operation. On the contrary, multicomponent glasses, particularly phosphate glasses,6 can easily accommodate a high concentration of rare earth without concentration quenching. For instance, the content of Nd31 can reach more than 2 1020 cm3 in commercial laser phosphate glasses.7 A phosphate glass is thus chosen as the host material in this investigation. In view of four-level transition nature of Sm31 visible laser oscillation,8 the laser a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2012.119 J. Mater. Res., Vol. 27, No. 16, Aug 28, 2012
http://journals.cambridge.org
Downloaded: 10 Dec 2014
threshold is expected to be low. In addition, Sm31 ions have wide absorption peaks from the UV to blue wave length region. Conveniently, it permits pumping with GaN LDs. As a first step to realize a visible fiber laser of Sm31-doped phosphate glass, this work concentrates on the spectroscopic properties of the bulk glasses. Absorption spectra, static excitation and emission spectra, time-resolved luminescence spectra, fluorescence lifetime, and quantu
Data Loading...
