RESEARCH ARTICLE Optical properties of Sm 3+ ions in sol-gel derived alumino-silicate glasses Litul Bokatial & S. Rai Received: 13 January 2011 / Accepted: 28 February 2012 / Published online: 3 April 2012 # Optical Society of India 2012 Abstract Sol-gel glasses of SiO 2 -Al doped with Sm 3+ ions were prepared with various concentrations of Al varied from 0.01 M to 0.05 M. Optical properties of Sm 3+ in sol gel silicate glasses were investigated. The photoluminescence intensity of the glasses increased significantly in presence of aluminum and annealing temperature. This can be explained due to the preven- tion of the cross-relaxation process in these glasses. Absorption and photoluminescence spectra showed that some of the Sm 3+ ions in the glass sample were reduced to Sm 2+ ions. Keywords Sol-gel . Photoluminescence . Aluminum . Annealing temperature . Cross-relaxation Introduction Previously we have reported certain important results from our studies carried out on Nd 3+ , Eu 3+ , Ho 3+ , Er 3+ and Tb 3+ doped with aluminum to verify the effects of the network modifier [1–3]. In our present work, we used another rare earth ion Sm 3+ as dopants. Glass host material is very important factor for developing rare earth-doped optical devices. In the light of rapid growth of optoelectronic based applications such as lasers, fiber communications, sensors and optical memory devices [4, 5], glasses are considered to be more favorable host material for high-density optical memory than crystalline matrices, because of the in- homogeneous width of the f-f transitions. There is large freedom in size and shape, in production; and it is also less expensive. The sol-gel synthesis used here is a low-temperature method for preparing optically transparent, amorphous hosts for rare earth (RE) ions. Sol-gel derived SiO 2 glasses and xerogels are very strategic amorphous materials of nanometer size po- rous structures. Because of the manner in which the glass matrix is formed, sol-gel glasses readily accept a higher dopant concentration than traditional melt glasses without compromising structural and optical integrity. Sol-gel optical materials have diverse poten- tial applications in phosphor, laser, and amplifier tech- nologies, but low fluorescence yields have hindered their practical use in many cases. There- fore the design of new silicate glass host for realizing intense luminescence from sample is a target at present. It is known that aluminum and CdS are used for prevention of aggregation of rare-earth oxide in the silica matrix [6, 7]. One of the most important concerns in rare earth doped glasses is to define the dopant environment; how- ever their intensities are strongly dependent on the host in which the rare earth ions are embedded. J Opt (April–June 2012) 41(2):94–103 DOI 10.1007/s12596-012-0069-x L. Bokatial : S. Rai (*) Laser and Photonics Laboratory, Department of Physics, Dibrugarh University, Dibrugarh, Assam 786004, India e-mail: srai.rai677@gmail.com L. Bokatial e-mail: ltlbktl@gmail.com