Three-dimensional object imaging with vortex wave tomography

The vortex electromagnetic (EM) wave carrying orbital angular momentum (OAM) has been developed as a new paradigm for object imaging, which exploits the dual relationship between the OAM index and the azimuthal angle to reconstruct the object azimuth profiles. In this paper, the tomography vortex wave radar is proposed to reconstruct the three-dimensional target information by exploiting the signal bandwidth, OAM degree of freedom and tomographic technique. The generated vortex waves are presented by analyzing the intensity and wavefront distributions, and the three-dimensional imaging model is built. Subsequently, the two-dimensional imaging method is proposed to remove the negative influence of the Bessel function modulation, and the three-dimensional imaging algorithms are developed to obtain the target's position in range, azimuth and elevation dimensions. Results show good agreement with the theoretical analyses, which provide robust three-dimensional imaging performance for multiple targets located at different elevation angles and achieve super-resolution in the azimuth dimension. This work can advance the development of three-dimensional imaging technology with stare illuminating manner.