| 149. | Large birefringence and polarization holographic gratings formed in photo-cross-linkable polymer liquid crystals comprising bistolane mesogenic side groups, A. Emoto, T. Matsumoto, T. Shioda, N. Kawatsuki and H. Ono, J. Appl. Phys. 106 (2009) 073505. |
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Abstract |
| Thermally stable polarization gratings with large birefringence are formed in photoreactive polymer liquid crystals with bis-tolane moiety and the terminal cinnamic acid moiety by the use of polarized ultraviolet interference light and subsequent annealing. The polarized ultraviolet light causes the axis-selective photoreaction between cinnamic acid groups and subsequent annealing induce reorientation of peripheral molecules without cross-linking along the cross-linked groups. Long bis-tolane mesogenic moiety exhibits large birefringence in comparison with a biphenyl mesogenic moiety, the value of the induced birefringence in the bis-tolane mesogenic liquid crystalline polymer is strongly dependent on both the grating constant and the wavelength of the reconstruction light. |