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.


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.

Get Full Text