Back Cover: Spatially Resolved Organic Whispering‐Gallery‐Mode Hetero‐Microrings for High‐Security Photonic Barcodes

Whispering-gallery-mode (WGM) microcavities featuring distinguishable sharp peaks in a broadband exhibit enormous advantages in the field of miniaturized photonic barcodes. In their Research Article (e202310263), Zhenhua Gao, Yong Sheng Zhao et al. have developed a surface tension assisted heterogeneous assembly strategy to construct WGM hetero-microrings through regulating the charge-transfer (CT) interactions along circular boundaries, which remarkably promotes the security level and encoding capacity of the barcodes.