Abstract
Holographic gratings were recorded in hybrid cells of the nematic liquid crystal E7 doped with multi-walled carbon nanotubes in a degenerate two-wave-mixing experiment. The hybrid structure comprises doped nematic contained between photoconducting polymeric layers of poly(N-vinylcarbazole) spin-coated on two indium-tin-oxide-covered glass plates. Multiorder diffraction was observed and the first-order self-diffraction efficiency was obtained in order to investigate the properties of the gratings. The hybrid cells showed quite high diffraction efficiency up to 47%, which is far beyond the theoretical limit of 34% predicted by the Raman-Nath theory. In addition, such a structure was shown to exhibit the photorefractive effect due to the presence of two-beam-coupling gain. Under the condition for a fixed total intensity of the two interfering beams, the gain was found to increase with increasing pump-to-probe beam-intensity ratio.
| Original language | English |
|---|---|
| Article number | 59470F |
| Pages (from-to) | 1-8 |
| Number of pages | 8 |
| Journal | Proceedings of SPIE - The International Society for Optical Engineering |
| Volume | 5947 |
| DOIs | |
| State | Published - 2005 |
| Event | Liquid Crystals: Optics and Applications - Warsaw, Poland Duration: 30 Aug 2005 → 1 Sep 2005 |
Keywords
- Carbon nanotubes
- Diffraction gratings
- Liquid crystals
- Photorefractivity
- Polymers