An optical device is provided, which includes a first transparent substrate, a second transparent substrate, and a liquid-crystal material disposed between the first transparent substrate and the second transparent substrate. The liquid-crystal material includes a photo responsive material with a chemical structure of: wherein A1 is A2 and A3 are independently X is halogen. R is H, C1-12 alkyl group, or C1-12 alkoxy group. R′ is C1-12 alkyl group.