We present measurements of the optical absorption cross section of the 4 I15/24 I13/2 transition at 1.5 μm of Er3+ ions embedded in SiO2 and Si-rich oxide, using cavity ringdown spectroscopy on thin films. The peak absorption cross section for Er3+ embedded in Si-rich oxide (10 at. % excess Si) was found to be (8±2)×10−21 cm2 at 1536 nm, similar to typical values for Er embedded in SiO2. The data imply that the silicon nanoclusters incorporated in Si-rich oxide do not enhance the peak cross section of the Er3+ 4 I15/24 I13/2 transition by 1-2 orders of magnitude, contrary to what has been reported in earlier work.

Appl. Phys. Lett.
Photonic Materials

Mertens, H, Polman, A, Aarts, I.M.P, Kessels, W.M.M, & van de Sanden, M.C.M. (2005). Absence of the enhanced intra-4f transition cross section at 1.5 μm of Er3+ in Si-rich SiO2. Appl. Phys. Lett., 86(Article number: 241109), 1–3. doi:10.1063/1.1949720