2.75 μm spectroscopic properties and energy transfer mechanism in Er/Ho codoped fluorotellurite glasses

Abstract We report a detailed spectroscopic investigation of a series of fluorotellurite glasses with different Er 3+ ions concentration in system 50TeO 2 -27BaF 2 -9ZnF 2 -8YF 3 -3MgF 2 -3NaF-xErF 3 -1HoF 3 (x = 1,2,3 mol%). Intense 2 μm emission and 2.75 μm emission with high absorption and emission cross-section were observed under 980 nm LD pumping, and the maximum gain coefficient around 2750 nm was as high as 2.41 cm −1 , suggesting the prepared glasses are a competitive candidate for mid-infrared laser materials. Besides, it was found that the trend of 2 μm and 2.75 μm emission intensity varied with Er 3+ ions concentration was different. Energy transfer process was discussed subsequently to explain this phenomenon. Furthermore, we quantitatively investigate the energy transfer efficiency from Er 3+ : 4 I 13/2 level to Ho 3+ : 5 I 7 level.