Enhanced photorefractive performance of the nematic liquid crystal cell containing photoconductive polymer film

Abstract

Photorefractive (PR) nematic liquid crystals (NLCs) possess large optical non-linearity but coarse grating spacings (tens of microns) and slow response time (generally in the order of 1 s). Here we presented a great improvement in PR performance of NLC cells containing photoconductive films as aligning layers by varying the thickness and the sensitizer concentration of the photoconductive layer to enhance the surface electric field modulation. As a result of optimising, considerable diffraction efficiencies and the response time as fast as tens of milliseconds were obtained from steady-state PR gratings within a wide range of grating spacings from 30 to 0.7 μm. Besides, the grating response was enhanced significantly compared with the previous reports under similar experimental conditions.

Keywords:

• liquid crystals
• photoconductive film
• surface-mediated photorefractive effect

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 61107044]; Program for Innovation Research of Science in Harbin Institute of Technology [PIRS of HIT A201420, PIRS of HIT A201421], and Postdoctoral Startup Foundation of Heilongjiang Province [LBH–Q13071].