All-Optical, Photonic Band Gap Modulation in Azobenzene Liquid Crystal Doped Cholesterics (Preprint)

摘要

Cholesteric liquid crystals doped with high clearing temperature azobenzene liquid crystals are shown to possess large, fast, and reversible dynamic photosensitive features. Selective wavelengths shifts approaching 400 nm are reported and depending on the host cholesteric liquid crystal, both red- shifted and blue-shifted wavelength changes can be induced. The photoinduced states of these material systems are shown to be stable for long periods of time upon removal of the radiation source, completely reversible, and dynamically fast. These phototunable features were demonstrated using both CW and nanosecond laser beams. The latter was used to change the selective reflection wavelength from blue to green with a single nanosecond pulse and the ability to write information into these films using these processes were demonstrated.