Optical and structural properties of Pr:GGG crystalline thin film waveguides grown by pulsed-laser deposition

Crystalline doped Gd3Ga5O12 ( Pr: GGG) thin films were grown by pulsed laser deposition (PLD) on yttrium aluminium garnet (YAG) substrates. The chemical composition and structural properties of the films were studied using Rutherford backscattering and X-ray diffraction, respectively. A strong influence of the oxygen pressure on the gallium content in the films as well as in the target surface was found. Films deposited at lower temperature or lower oxygen pressure are amorphous or Ga deficient. Well crystallised and stoichiometric GGG films were fabricated at 800 degrees C in the 5 to 10 Pa oxygen pressure range. These films present blue, orange and red fluorescence emissions from P-3(0) and D-1(2) levels of Pr3+ ions and fluorescence decay times which are similar to those of the bulk single crystal. Their refractive index of 1.964 close to the bulk crystal value and their waveguiding propagation attenuation of 1.0 +/- 0.3 dB/ cm measured at 632.8 nm wavelength indicate promising waveguiding properties.