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Optical properties of CaGd4Si3O13 (CGS) crystals with Er3+ used as 1.5 µm laser material

The Stark structure of the 4I13/2 and 4I15/2 multiplets of the Er3+ ion in CaGd4Si3O13 (CGS) was determined. The transition cross-sections have been obtained from the absorption and the luminescence spectra. The emission cross-section for π-polarization in the 1529.5 nm luminescence band is equal to 2.1×10-20 cm2. A gain curve has been plotted for π-polarization, and positive amplification occurs at 1550 nm. A wide luminescence band makes it possible to obtain tunable generation in the range 1540-1590 nm. The spectral parameters of the crystals Er, Ce:CGS indicate ample scope for developing an effective 1.5 µm laser with semiconductor pumping.