Formation of infrared femtosecond laser induced colour centres in Tb3+-doped and Tb3+/Ce3+-codoped heavy germanate glasses

The formation of infrared femtosecond laser induced colour centres was observed in Tb3+-doped and Tb3+/Ce3+-codoped heavy germanate glasses. A rectangular scan was made by focusing the laser beam inside the glass samples. A three-dimensional yellowish block was created from the path and it corresponded to the appearance of broad absorption bands in the absorption spectra. The irradiation induced absorption coefficient μ(λ) was used to characterize the distribution of radiation induced colour centres in the samples, whose peak was located at 380 nm and extended to the longer wavelength. Ce3+ ions were found not only to inhibit the formation of colour centres, but also to enhance the recovery. \pacs{61.80.Ba, 73.61.Jc, 74.25.Gz, 76.30.Kg, 73.43.Fj