Luminescence and photoinduced absorption in ytterbium-doped optical fibres

Photodarkening of Infrared Irradiated Yb3+-Doped Alumino-Silicate Glasses: Effect on UV Absorption Bands and Fluorescence Spectra

“…Two characteristic bands of pristine and irradiated samples were observed in the following range: P1 at 231-239 nm (5.4-5.2 eV) and P2 at 93-183 nm (13.3-6.8 eV) which yielded good correspondence with what previously reported in literature [10]. The P2 band could be due to three simultaneously excited ion pairs interaction [10] and its maximum position showed wider spectra of energies in our experiments. In Figure 4 the intensity of the P1 band is shown as a function of dopant concentration for pristine and irradiated samples.…”

“…Fit curve for pristine set of samples, although based on only four samples, appeared as linear while for the irradiated samples non-linear with a power of 3.6. Considering literature, P1 band is dependent on host composition [9] and ascribed to different origins: simultaneous Yb 3+ -Yb 3+ pairs excitation [10], Yb 3+ ions and oxygen deficiency centers (ODC) [11,12], charge-transfer (CT) absorption band [9]. From Figure 4 it can be noted that P1 band depends on Yb 3+ concentration which is in accordance with [8].…”

“…In particular, it is evident that the area under UV band linearly increases with increasing the Yb 3+ ion concentration for both, pristine and irradiated glass samples ( Figure 2). The importance of indicated UV band lays in its correlation with mechanism of PD [6,[8][9][10][11][12]. A Gaussian deconvolution curve for irradiated 1 wt% Yb 3+ sample was shown in Figure 3 as an example.…”

“…However, in Figure 4 there seems to exist a critical concentration of around 1 wt% of Yb 3+ ions above which the non linear growth is observed for the irradiated samples: thus the nonlinear growth of P1 after the irradiation should be mainly related to the Yb 3+ -Yb 3+ pairs interaction influenced by UV light. The increase of dopant concentration enhances cooperative luminescence (CL) which is probably one of the paths in which PD can occur [10]. CL should be involved in PD mechanism especially for higher dopant concentrations and additionally accelerate the process causing nonlinear effects [10,16].…”

Charge transfer processes and ultraviolet induced absorption in Yb:YAG single crystal laser materials

“…24 In particular, energy transfer between Yb 3þ and Yb 2þ ions has been suggested as a possible route for the observed loss mechanisms. However, no experimental evidence has, to the best of our knowledge, been presented for such an energy transfer.…”