Dynamically Tunable Optical Cavities with Embedded Nematic Liquid Crystalline Networks

Tunable metal-insulator-metal (MIM) Fabry-Perot (FP) cavities that can dynamically control light enable novel sensing, imaging and display applications. However, the realization of dynamic cavities incorporating stimuli-responsive materials poses a significant engineering challenge. Current approaches rely on refractive index modulation and suffer from low dynamic tunability, high losses, and limited spectral ranges, and require liquid and hazardous materials for operation. To overcome these challenges, a new tuning mechanism employing reversible mechanical adaptations of a polymer network is proposed, and dynamic tuning of optical resonances is demonstrated. Solid-state temperature-responsive optical coatings are developed by preparing a monodomain nematic liquid crystalline network (LCN) and are incorporated between metallic mirrors to form active optical microcavities. LCN microcavities offer large, reversible and highly linear spectral tuning of FP resonances reaching wavelength-shifts up to 40 nm via thermomechanical actuation while featuring outstanding repeatability and precision over more than 100 heating-cooling cycles. This degree of tunability allows for reversible switching between the reflective and the absorbing states of the device over the entire visible and near-infrared spectral regions, reaching large changes in reflectance with modulation efficiency Delta R = 79%.

Automated summary

This study proposes a tunable metal-insulator-metal Fabry-Perot cavities that can dynamically control light for novel sensing, imaging and display applications. By utilizing reversible mechanical adaptations of a polymer network, dynamic tuning of optical resonances is demonstrated. Solid-state temperature-responsive optical coatings are developed to provide large, reversible and highly linear spectral tuning of FP resonances, allowing for reversible switching between reflective and absorbing states of the device with a modulation efficiency up to 79%.