Optical amplification in nematics doped with carbon nanotubes

Abstract

We present results on the orientational photorefractive effect in a mesogenic nematic doped with multiwalled carbon nanotubes. Efficient coherent-beam amplification of a signal beam by energy exchange with a pump beam was observed in homogeneous cells of the doped liquid crystal E7 at electric fields of ∼0.5 V/μm. Photorefractive gains as high as 103 cm−1 are achieved in the Raman–Nath regime. It is found that the gain coefficient depends strongly on the externally applied dc voltage, the pump/probe intensity ratio and the total input intensity.