Anchoring Strength Characteristics of Micro-Grating Structures Fabricated by Direct Laser Writing

Abstract

Alignment characteristics of nematic liquid crystals on micro-scale grating structures fabricated by direct laser writing employing two photon excitation has been investigated upon changing periods and heights of the grating. Liquid crystal was infiltrated in the cell made of a substrate with gratings and another glass substrate with polyimide rubbed in the direction almost parallel to the grating vector of the structure in order to realize a twisted nematic configuration. Anchoring energies of the gratings were evaluated using the torque balance method, and were confirmed to be proportional to the height and inversely to the period of the grating.

While the anchoring energy of the gratings turned out to be weaker compared to substrates treated by the conventional rubbing method, varying periods and heights of the grating allowed control of the anchoring energy.

Keywords:

• Direct laser writing
• nematic liquid crystal anchoring
• torque balance method