Optical gain and upconversion luminescence in LaF_3: Er, Yb nanoparticles-doped organic-inorganic hybrid materials waveguide amplifier

摘要

A LaF_3: Er, Yb nanoparticle-doped organic-inorganic hybrid materials waveguide amplifier is demonstrated using reactive ion etching. A maximum gain of approximately 6.8 dB is observed in a 20-mm-long waveguide. Under excitation at 976 nm, the waveguides emit a strong green upconversion luminescence. The possible upconversion mechanisms are discussed. The dependence of upconversion emission intensity on excitation power confirms a three-photon process contributes to the upconversion of the emission band 405 nm and two-photon processes for the green and red emission bands. The temperature behavior by the measurement of the fluorescence intensity ratio of the signals at 520 nm and 544 nm as a function of the pump power demonstrates a fast thermalization between the ~2H_(11/2) and ~4S_(3/2) levels. The influence of upconversion emission on the gain performance of the waveguide amplifier is analyzed.