Generation of Bessel beams with 3D-printed lens

In this article, the 3D-printed dielectric lens is proposed to generate Bessel beam in millimeter-wave band. The dielectric lens is made of many square unit cells with the side length of a half wavelength. The unit cells with different thicknesses generate different insertion phase shift to the transmitted millimeter wave. The insertion phase distribution of the lens is calculated by comparing the phase distributions of the incident Gaussian beam and the desired output Bessel beam. Three types of lenses are simulated and fabricated using 3D printing technology with Nylon. The measured magnitude and phase distributions of zero-order Bessel beam agree with the simulated results very well and the measured phase distributions of the first-order Bessel beam carry orbital angular momentum.