Terahertz phase imaging provides access to refractive-index variations that are poorly captured by intensity-only methods. This work develops advanced computational approaches to improve THz phase reconstruction and spatial resolution. A quasi-Newton optimization method using analytical derivatives enhances the accuracy and convergence of multi-plane phase retrieval.
A time-resolved synthetic-aperture approach combined with Nesterov acceleration exploits multi-angle illumination to increase spatial information. Finally, experimental THz Fourier ptychography is demonstrated with motorized multi-angle illumination, aberration correction and angle calibration. These advances increase the effective numerical aperture and space-bandwidth product of THz systems. They enable more accurate phase reconstruction, faster convergence and significantly improved spatial resolution.
