Two-wave mixing in a nematic liquid-crystal film sandwiched between photoconducting polymeric layers

摘要

Degenerate two-wave-mixing effects were observed in hybrid cells of carbon-nanotube suspension in a nematic liquid crystal sandwiched between photoconducting polymeric layers in the presence of an externally applied dc field. First-order self-diffraction efficiencies as high as 47 percent were achieved from Raman-Nath gratings recorded in the cells. The beam-coupling ratio increases with increasing the pump-beam intensity for a fixed dc voltage. Experimental results show that a lower polymeric molecular weight of photoconducting layers leads to a higher two-beam-coupling ratio.