Terahertz transmission tomography enabled by focal plane array detection

This paper presents a terahertz transmission tomography system that integrates an optically pumped 2.52 THz laser with a high-speed focal plane array (FPA) detector for rapid three-dimensional imaging of small-scale samples. The FPA detector acquires a complete 180° projection dataset in just 8 min, significantly reducing imaging time compared to conventional point-by-point scanning systems. Projection data are reconstructed via a filtered back-projection algorithm optimized with a Hamming filter, effectively balancing noise suppression and structural fidelity. Quantitative evaluation shows that the Hamming filter achieves an SNR of 1.42 (versus 1.35–1.38 for the Ram–Lak and Shepp–Logan filters), maintains structural entropy at 6.36 (comparable to 6.36–6.37), and provides a 64% reduction in edge artifacts (Laplacian variance 0.0048 versus 0.0117). Three-dimensional reconstruction of a PTFE hose confirms the system’s ability to resolve multilayer structures with minimal distortion, underscoring its potential for non-destructive testing and biomedical imaging.