Absence of the enhanced intra- 4f transition cross section at 1.5 μm of Er3+ in Si-rich SiO2

Abstract

We present measurements of the optical absorption cross section of the I 152 4 → I 132 4 transition at 1.5 μm of Er3+ ions embedded in Si O2 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 Si O2. The data imply that the silicon nanoclusters incorporated in Si-rich oxide do not enhance the peak cross section of the Er3+ I 152 4 - I 132 4 transition by 1-2 orders of magnitude, contrary to what has been reported in earlier work. © 2005 American Institute of Physics.