About the cover: Advanced Photonics Volume 7, Issue 4

Integrated photonics has transformed optical technology, yet conventional on-chip waveguides remain constrained to planar geometries with limited design flexibility.At the same time, applications spanning chiral sensing, quantum optics, nonlinear optics, and lab-on-chip spectroscopy require more versatile waveguide platforms for strong light-matter interaction.In this issue, researchers introduce the concept of the twisted hollowcore light cage, a chiral on-chip waveguide platform with an air core fabricated via 3D nanoprinting.These sidewise-open structures leave the air core accessible to external species while their built-in twist imparts a strong chiral response, achieving twist rates and circular dichroism over two orders of magnitude higher than in twisted hollow-core fibers.The cover of Advanced Photonics Volume 7, Issue 4, features a schematic of the chiral waveguide transmitting one circular polarization.By uniting hollow-core guidance, lateral accessibility, and structural chirality, twisted light cages offer functionalities that surpass those of conventional on-chip waveguides and twisted fibers, establishing a new building block for integrated chiral photonics.The image is based on the research presented in the article by