Advancing multi-wavelength photoelasticity through single-exposure detection

In this paper, we present a method to expedite multi-wavelength photoelasticity for efficient stress analysis. By modulating two slightly different-wavelength illumination beams and simultaneously capturing dark-field and bright-field images, our approach acquires four essential polarized images. Spatial filtering of Fourier transforms streamlines inner stress computation, enabling multi-wavelength photoelasticity with a single detector exposure. Theoretical foundations are outlined, and proof-of-principle experiments validate the feasibility with a measurement error below 6.4%. The high measurement speed, determined by the detector's frame rate, facilitates dynamic sample measurements at video frequency, offering promising advancements in material stress analysis.