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 including a photo responsive material with a chemical structure of: as shown in the description, wherein A1 is as shown in the description, and A2 and A3 are respectively selected from as shown in the description. X is halogen. R is H, C1-12 alkyl group, or C1-12 alkoxy group. R' is C1-12 alkyl group.