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arXiv · 2512.04783

Terahertz Fourier Ptychographic Imaging

Pitambar Mukherjee·Vivek Kumar·Frederic Fauquet·Amaury Badon·Damien Bigourd·Kedar Khare·Sylvain Gigan·Patrick Mounaix
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Abstract

High-resolution imaging in the terahertz (THz) spectral range remains fundamentally constrained by the limited numerical apertures of currently existing state-of-the-art imagers, which restricts its applicability across many fields, such as imaging in complex media or nondestructive testing. To address this challenge, we introduce a proof-of-concept implementation of THz Fourier Ptychographic imaging to enhance spatial resolution without requiring extensive hardware modifications. Our method employs a motorized kinematic mirror to generate a sequence of controlled, multi-angle plane-wave illuminations, with each resulting oblique-illumination intensity image encoding a limited portion of the spatial-frequency content of the target imaging sample. These measurements are combined in the Fourier domain using an aberration-corrected iterative phase-retrieval algorithm integrated with an efficient illumination calibration scheme, which enables the reconstruction of resolution-enhanced amplitude and phase images through the synthetic expansion of the effective numerical aperture. Our work establishes a robust framework for high-resolution THz imaging and paves the way for a wide array of applications in materials characterization, spectroscopy, and non-destructive evaluation.

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Pitambar Mukherjee, Vivek Kumar, Frederic Fauquet, Amaury Badon, Damien Bigourd, Kedar Khare, Sylvain Gigan, Patrick Mounaix. 2025-12-04. Terahertz Fourier Ptychographic Imaging. https://arxiv.org/abs/2512.04783

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