Chiral photonic-band structure provides technical benefits in the form of a self-assembled helical structure and further functional wavelength tunability that exploits helical deformation according to pitch changes. The stopband wavelength control of the chiral photonic-band structure can be obtained by individual electrical methods or mechanical stretching deformation approaches. However, research on combined electric control of stretchable chiral photonic-band wavelength control while ensuring optical stability during the tuning process has remained limited till now. In this study, using the hybrid structure of elastomeric mesogenic chiral photonic gels (CPGs) with an electrically controlled dielectric soft actuator, we report the first observation of electrically stretchable CPGs and their electro-mechano-optical behaviors. The reliable wavelength tuning of a CPG to a broadband wavelength of ∼171 nm changed with high optical stability and repeated wavelength transitions of up to 100 times. Accordingly, for the first time, electrical wavelength tuning method of stretchable chiral liquid crystal photonicband structure was investigated.

We introduce an optically controllable color filter model using bi-layered CLC structure. From mathematical parameter sweep analysis using 4×4 matrix method, wavelength controls of red, green, and blue optical color filters and tailored tuning of optical purity in terms of FWHM from 105 nm down to 21 nm at green colored position were confirmed. In addition, an improved color gamut of optical color filters up to 162% of sRGB space in CIE 1931 was first reported. Facile design of custom color filter with controlled wavelength and FWHM, along with enhanced color gamut, can be used for various optical applications.

Structural color can be produced by nanoperiodic dielectric structures using soft materials. Chiral photonic elastomers (CPEs) produced from elastic chiral liquid crystal molecules can self‐organize into a helical nanostructure, and the chiral nanostructural color can be tuned by stretching. However, the ability to control the separation of biomimetic multicolors for practical applications beyond simple uniaxial stretching of single‐colored structures has been limited until now. Here, stretchable CPEs with simultaneous multicolor control, including electrical control, are presented. By engineering the heterogeneous elastic modulus of the CPEs, stretchable and simultaneous multicolor separations from an initially homogeneous color are realized. Electrically stretchable multicolor separation is investigated using a hybrid CPE structure on dielectric elastomer actuators, and multiarrayed color binning and chameleon‐like photonic e‐skin are further developed for device applications. Moreover, multicolor concealed camouflage switching and control of invisible photonic e‐skin are demonstrated. This multicolor control of stretchable photonic systems improves the functionality of various potential photonic applications.

Optical signals necessitate using filters that selectively transmit or reflect light with the desired wavelength information. In visual imaging‐related devices, a color filter acts as a wavelength selector to extract certain information from the incident light. To overcome the limitations of commercial pigmented color filters, structural color filters with controllable photonic bandgaps (PBGs) have recently attracted significant interest. Especially, chiral liquid crystal (CLC) has been widely investigated for tunable color filters owing to its selective reflection. However, most of the research has been limited to the control of conventional reflection rather than transmission wavelength. This study proposes an electrically wavelength‐tunable color filter with high optical transmittance using a heterogeneous CLC with extremely small voltages not exceeding 1.4 V. Electrothermal tuning of CLC is approached so that transmission wavelength of the device can be tuned among red, green, and blue. Moreover, analog pixel binning using CLC color filters is explored in a tetra‐layout beyond state‐of‐the‐art pixel binning with post‐capture digital image processing. Dynamic and direct binning can prevent the quality degradation of the images captured under low‐light illumination in image sensors. The wavelength‐tunable transmission color filter proposed in this study is expected to facilitate future electro‐optical dynamic color filter applications.

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