Multi-Wavelength Filters of Templated Blue Phase Liquid Crystal

Abstract

The multi-wavelength filters in the visible light band using the blue phase liquid crystal (BPLC) template was investigated. A multi-layer templated BPLC (T-BPLC) filter without intermediate dielectric layers was fabricated, which may reflect multi-wavelength in one filter. Compared with the cholesteric liquid crystal (CLC) filter, the T-BPLC filter may get a much narrower reflection bandwidth (<15 nm), show better angular stability of incident light, and have a more stable wavelength and bandwidth with a temperature shift. Furthermore, the central wavelength and bandwidth can be easily controlled by the fabrication process and the optimization of the material concentration. When the incident angle varies, the shift of the center wavelength of the T-BPLC filter is much smaller than that of the CLC filter. The multi-wavelength filter shows a potential application in color filters and high-density wavelength division multiplexed networks.

Templated Twist Structure Liquid Crystals and Photonic Applications

“…As shown in Figure 6c, the maximal reflectance of the multi-chiral CLC filter is 69% for green color, which has improved by 75% compared to Since the bandwidth of CLC filters is too broad to apply in narrow band-gap filters and the central wavelength of CLC filters will shift after the templating process compared with the templated-BPLC filters, the templated-BPLC with a narrow reflection band is highly desirable to achieve narrow band-gap filters. Zha et al investigated a multi-wavelength filter in the visible light band based on the BPLC template [81]. In their study, a narrow bandwidth multi-wavelength BPLC device using a polymer template was fabricated, which can realize multi-layer twist structure LC device without the intermediate layer and reflect multiple wavelengths at the same time.…”

33.2: A Tunable Filter with Single Layer Twist Structure Liquid Crystals

“…An electrically induced broad bandwidth CLC filter was proposed [17]. The multi-pitch filters based on twist structure LCs have been fabricated [18][19]. A method for fabricating a multi-pitch CLC film with single layer by utilizing a polymer template has been demonstrated [18].…”

High-Reflective Templated Cholesteric Liquid Crystal Filters

“…Various types of optical filters, such as Bragg grating filters, color filters, and waveguide filters, have been developed [3][4][5][6]. For the LC materials among optical filters, cholesteric liquid crystals (CLCs) have been widely applied due to their self-assembled structures and simple fabrication [7]. The CLCs possess the intrinsic features of pitch-and polarization-selective reflection of the incident light [8][9][10][11][12].…”