Biomimetic macroscopic hierarchical moire gratings.

Area of Science:

• Materials Science
• Nanotechnology
• Optics

Background:

• Moire gratings are periodic structures with unique optical and mechanical properties.
• Azobenzene molecular glass thin films are photoresponsive materials with potential for nanostructure fabrication.
• Hierarchical structures offer enhanced functionality compared to simple gratings.

Purpose of the Study:

• To fabricate large-scale hierarchical macroscopic moire gratings on azobenzene molecular glass thin films.
• To investigate the formation of nanostructured linear and crossed moire gratings with controllable pitch values.
• To characterize the hierarchical structures of the fabricated moire gratings.

Main Methods:

• Fabrication using a Lloyd's mirror interferometer, an all-optical technique.
• Characterization using atomic force microscopy (AFM), scanning electron microscopy (SEM), optical microscopy, and surface profilometry.
• Utilizing the photoresponsive properties of azobenzene molecular glass thin films.

Main Results:

• Successfully fabricated large-scale hierarchical macroscopic moire gratings resembling Peruvian lily flower petals.
• Achieved nanostructured linear and crossed moire gratings with pitch values up to several millimeters.
• Demonstrated two-fold and three-fold hierarchical structures in the obtained gratings.
• Confirmed the effectiveness of the simple all-optical fabrication technique.

Conclusions:

• The Lloyd's mirror interferometer is an effective all-optical method for creating large-scale hierarchical moire gratings on azobenzene films.
• The fabricated gratings exhibit controllable hierarchical structures and tunable pitch, opening possibilities for advanced optical and material applications.
• This technique offers a scalable and precise approach to nanostructure fabrication for future material design.