Microsecond high‐contrast continuous 2.25π phase modulation based on non‐linear Kerr effect of vertically aligned deformed helix ferroelectric liquid crystal

Abstract

Here we disclose a fast (ON time ∼50 μs and OFF time ∼25 μs at 55 °C), high‐contrast, continuous phase modulator without fringe field effect (FFE). The phase modulator uses the Kerr effect of vertically aligned deformed helix ferroelectric liquid crystals (VADHFLCs). Specifically, FFE is a long‐term problem for nematic liquid crystals (NLCs). In this article, we are disclosing, for the first‐time found, that no FFE exists for VADHFLCs, even for phase modulator with 1‐μm pixel pitch. It is an attractive feature for ultra‐high‐resolution display and photonic applications. Moreover, the Kerr constant is 88 nm/normalV2, and the contrast ratio is larger than 1000:1. It is a promising candidate for high‐PPI augmented reality (AR)/virtual reality (VR) displays, wavelength selective switch (WSS), hologram, adaptive optics, and LiDARs.

Reconfigurable Geometrical Phase Spatial Light Modulator Using Short-Pitch Ferroelectric Liquid Crystals

“…The Deformed Helix Ferroelectric Liquid Crystal (DHFLC) with sub-wavelength helix pitch can provide continuous amplitude modulation without fringe eld effect (FFE.) 34,35 . The DHFLC, on applying the electric elds, shows a continuous change of effective birefringence and the optical axis, resulting in analog grayscale 36 .…”

“…However, there are certain limitations, such as loss of light due to the imperfect alignment in the DHFLC that limits the e ciency and contrast ratio in these devices 36 . Additionally, the effective birefringence and effective optical axis change simultaneously 32,35 . The variation of the retardation limits the multi-phase level and phase modulation depth.…”