The large volumes induced by complex free‐space optical paths pose a challenge to quantum precision measurement and optical communication in traditional optics. Meanwhile, on‐chip integration is an important requirement for quantum technology. To simplify complicated optical systems, the development of miniaturized and integrated devices with a variety of structures, such as optical waveguide, microcavity, photonic crystal, and metasurface, has attracted increasing attention. Herein, on‐chip light–atom interactions affected by these nanostructures from the aspects of recent advancement in their physics and applications are reviewed. In recent years, different nanostructures are used to realize the functions of macro‐optical systems. The structural characteristics, interaction mechanisms, and main achievements in terms of the applications of the corresponding devices are demonstrated and compared. Finally, the research trends and challenges as well as the scope for future work are discussed.

Nanophotonics There have been numerous studies of on‐chip different nano‐structures such as waveguides, microcavities, photonic crystals, and metasurfaces, used for realizing the functions of macro‐optical systems involving light‐atom interactions in recent years. The structural characteristics, interaction mechanisms, and main achievements in terms of the applications of the corresponding devices are demonstrated, summarized and compared. More information can be found in article number http://doi.wiley.com/10.1002/adpr.202200153 by Weiyi Wang, Zhen Chai, and co‐workers.