Multimodal fluorescence-coherence monitoring of polymer curing

This Letter presents a multimodal monitoring method based on combined fluorescence-coherence imaging for surface-interior polymer curing. The wavelength-selective absorption of fluorescence speckles is introduced to overcome speckle occlusion, and three spectral channels are developed to eliminate signal crosstalk with ultraviolet excitation, blue-speckle surface imaging, and near-infrared tomography. For validation, a dedicated system integrating fluorescent digital image correlation (FDIC) and optical coherence tomography (OCT) is custom-built to measure the curing process. The result highlights significant advantages in spatial and mechanistic measurement. By resolving deformation from surface to interior, the depth-dependent response of local curing behaviors is demonstrated. Moreover, by merging FDIC's macroscopic stability and OCT's microscopic sensitivity, this method realizes mechanism coverage that is unattainable by either technique alone.