Light-induced self-written waveguides based on NaYF4/polymer composites for the C-band amplification

We successfully synthesized Er3+/Yb3+/Ce3+-codoped cubic phase NaYF4 nanocrystals with the size of ∼14 nm by a solvothermal method. Under the excitation of a 976 nm laser diode, the as-prepared nanocrystals showed strong 1530 nm emissions and weak visible emissions. With the addition of Yb3+ ions, both visible and near-infrared emissions of Er3+ were enhanced. The addition of Ce3+ ions can effectively quench the visible emissions and increase the population of electrons on the 4I13/2 of Er3+ ions, further enhance the 1530 nm near-infrared emissions. The doping concentrations of lanthanide ions were carefully adjusted. It was found that the NaYF4 nanocrystals doped with 1% Er3+, 10%Yb3+, and 10%Ce3+ showed the most intense 1530 nm emissions. By dispersing the as-prepared nanocrystals in bisphenol A ethoxylate diacrylates (BPAEDA), the transparent nanocrystals doped polymer composite materials were prepared. By using the technique of light-induced self-written waveguide fabrication, NaYF4 nanocrystals doped waveguides with the length of 20 mm were prepared. Under the excitation of a 976 nm laser, the green visible light was observed from the waveguide devices.