Abstract
Recent development of controlling quantum systems has enabled us to utilize the systems for quantum computing, communication, and sensing. In particular, quantum sensing has attracted attention to a broad community of science and technology, as it could surpass classical limitations in measuring physical quantities such as electric and magnetic field with unprecedented precision. Among various physical platforms for quantum sensing, trapped-ion based system possesses several advantages-atomic size, outstanding quantum coherence, and quantum properties. In this review, we introduce previous research efforts to utilize the trapped-ion system for reaching ultimate sensitivity and discuss future perspective and research directions in this emerging field.