Hybrid fractional Fourier transform for filtering and imaging in a single digital holography workflow

We propose a hybrid fractional Fourier transform (hybrid FrFT) framework for off-axis digital holographic microscopy. This framework combines optical FrFT, implemented via a novel, to the best of our knowledge, three-lens object arm design, with digital FrFT filtering into a unified process. By replacing all FFT operations with FrFT, our approach adaptively minimizes conjugate overlap in spatial frequency distribution and improves the recovery of higher-frequency diffraction components. Both simulations and experimental results reveal significant enhancements in the resolution of amplitude and phase reconstruction while adhering to practical optical design constraints. (c) 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.