A study of thermally-induced optical bistability and the role of surface treatments in Si-based mid-infrared photonic crystal cavities

摘要

We report the observation of optical bistability in Si-based photonic crystalcavities operating around 4.5 \mum. Time domain measurements indicate that thesource of this optical bistability is thermal, with a time constant on theorder of 5 \mus. Quality (Q) factor improvement is shown by the use of surfacetreatments (wet processes and annealing), resulting in an increase of Q-factorfrom 11,500 to 29,300 at 4.48 \mum. After annealing in a N2 environment,optical bistability is no longer seen in our cavities.