Resolution Limits of Hyper-Hemispherical Silicon Lens-Integrated THz Cameras Employing Geometrical Multi-Frame Super-Resolution Imaging
In this paper, we present a comprehensive study to understand the image formation and associated resolution limitations of hyper-hemispherical high-resistivity floating-zone silicon (HRFZ-Si) lens-integrated terahertz (THz) cameras, and we extend this understanding into THz super-resolution imaging applications. Along these lines, design trade-offs between fixed field-of-view (FoV) and frequency-dependent angular resolution of such cameras are also discussed. The present study is based on investigations of a CMOS THz camera that is made of a 32×32-pixel focal plane array (FPA) sensor and a 15-mm diameter objective hyper-hemispherical HRFZ-Si lens. Two experiments are performed at 0.652 THz. In the first experiment, THz geometrical multi-frame super-resolution imaging is performed to demonstrate that such cameras can always reach the maximum achievable resolution in their entire operating bandwidth. In the other, a full radiation pattern scan is performed to measure aberrations of off-axis displaced pixels in order to give a comprehensive picture of the camera’s resolution behavior across the full camera frame. The investigations and discussions are general in nature and should be applicable to any broadband THz camera.
This document is the accepted manuscript version that has been published in final form in IEEE Transactions on Terahertz Science and Technology at https://doi.org/10.1109/TTHZ.2021.3063839.
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