Infrared and visible luminescence properties of Er3+ and Yb3+ ions codoped Ca3Al2Ge3O12 glass under 978 nm diode laser excitation

Er 3+ and Yb3+ ions codoped calcium aluminum germanate glass has been synthesized by solid-state reaction. An intense infrared emission at 1534 nm, which corresponds to the minimum losses of silica based fibers used in optical communications, and visible emissions at 416, 490, 525, 548, and 660 nm, corresponding to the I13/24→I15/24, H9/22→I15/24, F7/24→I15/24, H11/22→I15/24, S3/24→I15/24, and F9/24→I15/24 transitions of Er3+ ions, respectively, were simultaneously observed in this glass under the excitation of a 978 nm diode laser at room temperature. These emissions are mainly attributed to energy transfer from Yb3+ ions to Er3+ ions. The up-conversion processes involve a sequential two-photon absorption for the red (660 nm), the green emissions (525 and 548 nm) and the blue emission (490 nm), and a sequential three-photon absorption for the violet-bluish emission (416 nm). The up-conversion fluorescence of Ca3Al2Ge3O12:Er,Yb glass can be used to detect 980 nm infrared laser light.