Volume 95, Issue 10, 15 May 2004
Index of content:
- LASERS, OPTICS, AND OPTOELECTRONICS (PACS 42)
Faraday rotation spectra of bismuth-substituted rare-earth iron garnet crystals in optical communication band95(2004); http://dx.doi.org/10.1063/1.1707214View Description Hide Description
Bismuth-substituted rare-earth irongarnet (REBIG) crystals are used in optical isolators for optical communication. However, the Faraday rotation (FR) spectra of REBIG crystals in the wavelength region of 1.3–1.6 μm have not yet been theoretically studied. To interpret the spectra, we assumed that the FR in this wavelength range was dominated by the contribution of the electric dipole transitions, and calculated the FR spectra. REBIG bulk crystals were grown from the self-fluxed melt by the top-seeded solution growth method. The experimental results agreed with the theoretical calculation of FR in and The results indicate that the theoretical analysis method of the FR spectra of REBIG in the visible range of wavelengths can be applied in the optical communication band.
Optical properties of ions in oxyfluoride glasses and glass ceramics comparing different preparation methods95(2004); http://dx.doi.org/10.1063/1.1707204View Description Hide Description
A study of optical properties of doped oxyfluoride glasses and glassceramics prepared by three different methods has been carried out. These methods start from or a ion solution as doping agent. The alternative preparation method based on a preliminary dissolution of the ions is proposed in order to avoid nonhomogeneous dopant distribution and spontaneous devitrification during glass elaboration. In the frame of the Judd–Ofelt theory, main radiative parameters have been studied: transition probabilities, lifetimes, and stimulated emission cross sections. Fluorescence decay curves have been also analyzed in order to study the final distribution of the ions after the ceramming process, discerning between ions that reside in the fluoride nanocrystals precipitated during heat treatment and those remaining in the glassy phase. The based glassceramics present the best values for spectroscopic parameters as the stimulated cross section of the laser transition.
95(2004); http://dx.doi.org/10.1063/1.1707231View Description Hide Description
We used a regeneratively amplified Ti:sapphire femtosecond laser to create optical birefringence in an isotropic glass medium. Between two crossed polarizers, regions modified by the femtosecond laser show bright transmission with respect to the dark background of the isotropic glass. This observation immediately suggests that these regions possess optical birefringence. The angular dependence of transmission through the laser-modified region is consistent with that of an optically birefringent material. Laser-induced birefringence is demonstrated in different glasses, including fused silica and borosilicate glass. Experimental results indicate that the optical axes of laser-induced birefringence can be controlled by the polarization direction of the femtosecond laser. The amount of laser-induced birefringence depends on the pulse energy level and number of accumulated pulses.