Does ytterbium give emission in glasses when co-doping does not exist? If we doped only ytterbium in our samples what would be the excitation wavelength?
Hi, In regards to the co-doping, e.g. Yb and Er, there is an energy transfer mechanism between Yb and Er via the lattice, so one can generate higher gain per unit length of fibre/material. We mention it in Opt. Express, 15, 13155, 2007, and there are related references within.
Sole doping with Yb produces emission around 1.08um, but I've seen/used lasers based on Yb ranging from 1.014um to 1.12um.
Hi, In regards to the co-doping, e.g. Yb and Er, there is an energy transfer mechanism between Yb and Er via the lattice, so one can generate higher gain per unit length of fibre/material. We mention it in Opt. Express, 15, 13155, 2007, and there are related references within.
Sole doping with Yb produces emission around 1.08um, but I've seen/used lasers based on Yb ranging from 1.014um to 1.12um.
An additional reason to add Yb3+ as co-dopant is it's high absorption cross-section when compared with other lanthanides. For instance, in the mentioned case of Er3+/Yb3+, both ions absorb light at 980 nm, but the absorption of Yb3+ is several times stronger than Er3+ (the exact number depends on the host). Therefore, Yb3+ plays the role of sensitizer of the excitation light.
Generally, you can excite Yb3+ also at 920 nm, though the main absorption peak is normally around 980 nm.
Optimum performance of an active medium depends on how efficiently it can be excited and delivers the energy at required output region. that is why the visible region phosphors are excited in host absorption band or the strong f-d and CT bands of dopant lanthanides. In NIR region however, such strong absorption is absent and most lanthanide ions exhibit poor absorption cross-section. Using high dopant concentration is one option but it leads to concentration quenching above certain limit. Another option is codoping with suitable sensitizer. Yb3+ is most suitable for sensitization owing to its high absorption cross-section, high quantum yield and long decay lifetime (to facilitate energy transfer). Also Yb3+ does not exhibit cross-relaxation and therefore can highly be doped, which is advantageous for laser and upconversion applications. Many NIR and MIR emitting lanthandes exhibit resonant nature with Yb3+, which can be effectively excited by high power diode lasers at 980 nm.
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