A. Srinivasa Rao
The geometric phase of light is a fundamental and fascinating phenomenon in optics, associated with the evolution of various parameters of light, such as polarization, propagation direction, and phase. It is a well‐established concept and has recently found extensive applications, particularly in the development of geometric phase elements that enable efficient manipulation of light. This review presents a comprehensive and structured account of the geometric phase of light, tracing its evolution from the seminal work of Shivaramakrishnan Pancharatnam (1956) to recent advances in modern optics. This review focuses on establishing a unified understanding of the fundamental principles, theoretical frameworks, and key experimental realizations underlying the geometric phase. We systematically introduce the essential parameters and their associated representation spaces, followed by a coherent treatment of geometric phase in polarization, spatial, and vector modes, as well as in full electromagnetic field descriptions. Particular emphasis is placed on connecting these seemingly diverse manifestations through a common physical framework. We further provide a consolidated overview of the optical elements and experimental methodologies used for the generation and detection of geometric phase, highlighting their underlying physical mechanisms. In addition, this review offers critical insights into how foundational concepts have evolved into contemporary research directions. By integrating core concepts, experimental approaches, and interpretative perspectives in a single framework, this work aims to serve as a self‐contained resource for researchers seeking a deeper and more unified understanding of the geometric phase of light.