Tunable silicon-based light sources using erbium doped liquid crystals

Tunable emission in the near infrared is demonstrated on a silicon platform. The building blocks for the tunable light sources consist of porous silicon microcavities infiltrated with erbium doped nematic liquid crystals. Erbium ions are the luminescence source, porous silicon microcavities narrow the emission band, and liquid crystals enable tuning of the peak wavelength. Greater than 10 dB attenuation is achievable by thermal actuation with microcavities having a Q factor of 200. The bandwidth of the tunable emission is limited by the liquid crystal birefringence. (c) 2007 American Institute of Physics.