Effect on response time and diffraction efficiency of co-usage azo dye and carbon nanoparticle in nematic liquid crystal

• DOI: 10.1016/j.synthmet.2008.03.017
• Publication Date: 2008-05-04T02:36:05Z
• Authors: Oğuz Köysal; S. Eren San
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

Abstract In this work, the formation of the photo-induced grating and nonlinear optical properties such as diffraction efficiency ( η ), refractive index modulation (Δ n ), nonlinear index coefficient ( n 2 ) of nematic liquid crystal (E7) doped by azo dye ( Methyl Red) and C60 have been investigated by diffraction grating measurements. Diffraction efficiencies of 441 nm pump and 632 nm probe beams were measured in two-wave mixing experiment. Maximum diffraction efficiency was found 26% doped with both 1% MR and 0.5% C60, while cells without C60 had maximum diffraction efficiency of 19% under 30 mW laser illumination. Rise time was found to increase with Methyl Red concentration. The nonlinear index coefficient, n 2 , was calculated to be 11 × 10 −3 cm 2 /W and highly depend on MR concentration.