Low voltage tunable liquid crystal Fibonacci grating

ABSTRACT

In this article, we disclose low voltage tunable liquid crystal Fibonacci gratings (FbG). Photoalignment technique has been used to create two domains of Fibonacci structure using a photomask. Switchable properties of LC are used to tune the diffraction efficiency of different orders by modulating the phase using the electric field. Position of split first orders shows good agreement with the golden ratio characteristic of the FbG. An increase in first-order diffraction efficiency from 3.7% to 6.7% has been achieved with a response time of 5.1 ms. The diffraction almost diminishes at 15 V with a very fast response time of 100 µs, the relaxation time is relatively slower ~26 ms, which is primarily due to higher viscosity. Variation and switching of the intensity of different orders in FbG, by the application of the electric field, can be utilised for selective far-field super-resolution imaging and different photonic applications.

Graphical abstract

KEYWORDS:

• Liquid crystal
• Fibonacci grating
• optics
• diffraction

Acknowledgments

The financial support from the ITF Grant ITS/370/16 from ITC Hong Kong government and from the State Key Laboratory of Advanced Displays and Optoelectronics Technologies, Hong Kong University of Science and Technology are gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the ITC, Hong Kong Gov. [ITS/370/16].