Channeled spectropolarimetry: A review of technological evolution, algorithmic breakthroughs, and diversifying applications

Channeled spectropolarimetry (CSP) delivers single-shot, full-Stokes spectra without moving parts, yet three foundational limitations: (i) the mandatory pre-calibration of retarder phases, (ii) extremely strict alignment tolerances between retarders, and (iii) Fourier-domain crosstalk that degrades spectral resolution, have restricted various applications to early-stage designs. This Review dissects how twenty-six years of targeted research overcame each barrier. We spotlight five technical milestones: (1) self-calibration eliminating the pre-calibration step; (2) alignment-error compensation and arbitrary-angle architectures relaxing angular constraints; (3) single-retarder configurations halving hardware complexity; (4) beyond-Fourier algorithms suppressing crosstalk; and (5) imaging integrations enabling hyperspectral polarimetry. By mapping these advances and their performances together with the trade-offs, this work provides researchers and engineers with a concise roadmap for selecting CSP solutions matched to their specific scenarios ranging from semiconduction ellipsometry and endoscopic cancer detection to vehicle-mounted navigation.