摘要
THz imaging is to be used in many applications varying from semiconductor quality control, disease diagnosis, non-destructive investigations and security screening. What underpins this is the lenses used in the imaging design, and the normal spherical lens suffers from spherical aberrations that require concentrated effort to be removed. Here, we derive an analytical modification to the ordinary spherical lens formula that reduces the focal spot size of short-focal lens THz lenses. We 3D print our lenses to validate their performance.