ELECTRO-OPTICS  LABORATORY

Fresnel incoherent correlation holography (FINCH) is a three-dimensional imaging technique whose reconstruction quality is sensitive to the spectral bandwidth of the object. In this study, we present a practical post-recording method for extending the usable spectral bandwidth in FINCH. The proposed approach, termed post-acquisition spectral engineering for FINCH (PASE-FINCH), combines holograms recorded with different wavelength-dependent focusing errors to generate a synthetic hologram with improved spectral tolerance. Reconstruction is performed using a two-step computational procedure that consists of numerical back-propagation of the synthetic object hologram, followed by deconvolution with synthetic point spread holograms constructed from pre-recorded wavelength-dependent responses. All experiments were performed using a monochrome image sensor that lacks intrinsic color discrimination. Experimental results demonstrate improved spectral tolerance compared with conventional FINCH reconstruction and diffractive-lens-based imaging under similar conditions. A step-by-step experimental procedure, calibration strategy, and MATLAB-based reconstruction workflow are provided to facilitate reproducible implementation. The proposed framework enables broadband FINCH operation and supports the development of achromatic incoherent holographic imaging systems.