A review of spectropolarimetric imaging: Fundamentals, recent developments, and critical issues

Spectropolarimetric imaging, which integrates spectral and polarization information, has emerged as a powerful multidimensional imaging technique with remarkable advantages in remote sensing, environmental monitoring, biomedicine, astronomy, and nanophotonics. This paper reviews the development and current progress of spectropolarimetric imaging, with emphasis on free-space implementations including temporal modulation, division of aperture, division of amplitude, division of focal plane, and channel modulation, as well as emerging metasurface-based on-chip schemes. By analyzing the principles, performance characteristics, and representative applications of these methods, their strengths and limitations in terms of spatial resolution, spectral accuracy, system stability, and snapshot capability are highlighted. Furthermore, it is pointed out that device integration, algorithmic intelligence, and system miniaturization will be the key directions for future development. This review aims to provide systematic references for in-depth research and engineering applications, and to envision broad prospects in complex scene detection, aerospace missions, and chip-scale optical systems.