Metalens Enabled Terahertz Imaging for Non-Destructive Measurement

Terahertz imaging technology presents great potential for non-destructive measurement in industrial application, especially for non-polar (infrared inactive) materials including ceramics, plastics, etc. But its imaging resolution is generally limited to wavelength scale. Here, we have focused on the design and validation of a metalens operating at 0.14 THz by leveraging electromagnetic simulations to optimize its performance. The proposed metalens demonstrates excellent focusing abilities, enabling super-resolution imaging beyond the diffraction limit with the subwavelength resolution of 0.79λ. We further integrate this metalens into a terahertz non-destructive imaging system tailored for defect detection in printed circuit boards (PCBs), specifically targeting broken line defects. The experimental results have shown the measurement errors are less than 3%, underscoring the potential of the approach for precise and non-destructive measurement.