High-contrast, low-voltage variable reflector for unpolarized light

GRAPHICAL ABSTRACT

ABSTRACT

A thin, optically clear photonic system that switches between transmission and reflection mode with low-voltage application was developed using diffractive waveplates coupled to a cholesteric thin film. The system has no strongly absorptive components such as polarizers or filters and its peak transmission is determined by Fresnel losses only. The device makes use of unpolarized-to-polarized thin film converters wherein light propagation is controlled in inter-polarizer space. Switching between 70% and 0.8% transmission states with application of <2 V voltage is demonstrated.

KEYWORDS:

• Chiral liquid crystals
• diffractive waveplates
• electro-optics
• optical switch
• polarizer

Funding

This work was supported by the U.S. Air Force Research Laboratories and U. S. Army Natick Soldier Research Development and Engineering Center.