Spectral studies of erbium doped soda lime silicate glasses in visible and near infrared regions Y.K. Sharma a, * , S.S.L. Surana b , R.K. Singh a , R.P. Dubedi c a Department of Physics, Govt. P.G. College, Rudrapur 263 153, Udam Singh Nagar, Uttaranchal, India b Department of Physics, J.N.V. University, Jodhpur 342001, Rajasthan, India c Department of Chemistry, Govt. P.G. College, Pithoragarh 262502, Uttaranchal, India Received 18 May 2005; accepted 21 October 2005 Available online 18 January 2006 Abstract Optical absorption and photoluminescence spectra of Er 3+ doped soda lime silicate glasses of the composition (in wt.%) 68.94SiO 2 – 22.55Na 2 O–1.91CaO–4.96K 2 O–0.85B 2 O 3 –0.29As 2 O 3 –xEr 2 O 3 where x = 0.0, 0.2, 0.3 and 0.5 have been studied in the UV–VIS/NIR regions. From the measured intensities of the various absorption bands of these glasses, the Judd–Ofelt parameters X 2 , X 4 and X 6 have been evaluated. Judd–Ofelt theory has been successfully applied to characterize the absorption and luminescence spectra of these glasses. From this theory various radiative properties like spontaneous emission probability, radiative life time, fluorescence branching ratio and stimulated emission cross-section for various emission bands of these glasses in the visible and NIR spectral regions have been deter- mined and reported. An attempt has been made to through some light on the environment of Er 3+ in this glass system. Radiative prop- erties of fluorescence band at 1.54 lm suggest the suitability of this glass system for broadband amplifier in the third telecom window. Ó 2005 Published by Elsevier B.V. Keywords: Soda lime silicate glass; Rare earth doped glass; Optical Spectroscopy; Judd–Ofelt parameters 1. Introduction In recent years much attention has been devoted to the development of infrared lasers [1–3] and amplifiers [4–7] for telecommunication. Many rare earth doped glass matrixes [8] such as silicates, phosphates, borates, fluorides, etc. have been used to produce such active optical devices. The optical properties of Er 3+ are of particular interest in the pursuit of infrared lasers operating at eye-safe wave lengths and in the fabrication of optical amplifiers [4–7]. The electronic transition from the 4 I 13/2 energy level mani- fold to the 4 I 15/2 many fold of Er 3+ produces light at a wavelength approximately 1.54 lm which is outside the range of wavelengths focused on the retina of the human eye [9] and is close to the wavelength at which the attenu- ation of the signal in a glass fiber is lowest [4]. In the development of rare earth doped optical device, the host glass matrix is a very important factor to be con- sidered. The choice of suitable glass-forming and glass- modifier systems help in tailoring glass matrix to meet the specific requirements. So for, much effort has been spent on fluoride systems [10,11] owing to their lower pho- non energy as compared to oxide systems. On the other hand, the oxides are more useful than fluorides as host materials for practical applications due to their high chem- ical durability and thermal stability [12]. Among oxide glasses, phosphate and silicate glasses are the two most important hosts which have been used extensively for lasers and fiber amplifiers [13,14]. As compared to silicate glasses, phosphate glasses have their limited use because the phos- phate glasses are hydroscopic in nature [15] and have lower glass transition temperature. On the other hand silicate glasses have superior chemical resistance and are optically transparent at the excitation and lasing wavelengths [12]. Therefore, they are more compatible with the fabrication 0925-3467/$ - see front matter Ó 2005 Published by Elsevier B.V. doi:10.1016/j.optmat.2005.10.013 * Corresponding author. Tel./fax: +91 5944 243586. E-mail address: dryksharma@yahoo.com (Y.K. Sharma). www.elsevier.com/locate/optmat Optical Materials 29 (2007) 598–604