A Roadmap for the Generation of Bessel Beams: Challenges and Opportunities from Microwave to Terahertz Frequencies

The focused character and the limited-diffraction properties of Bessel beams make them attractive in various modern applications, such as wireless power transfer, medical imaging, chip-to-chip communications, and so on. While devices capable of generating Bessel beams at optical frequencies are now widespread, the microwave and terahertz (THz) wave generation of Bessel beams is more recent. In this contribution, we aim at giving the reader a clear perspective on the potentialities offered by Bessel beams as well as on the difficulties that still hinder their full development in certain frequency ranges. Starting from well-consolidated techniques, we discuss the recent advances in their efficient generation from the microwave to the THz domain. An outlook on possible future theoretical and practical developments in this field is finally provided.