Tunable terahertz Bessel beams with orbital angular momentum

Abstract

In this work we demonstrate a frequency-tunable terahertz (THz) Bessel beam with zero- and first- order modes and orbital angular momentum, by utilizing a Tsurupica Axicon lens in combination with a picosecond difference frequency generation laser. This system enabled the selective generation of zero- or first-order THz Bessel beams with frequency-tunability across the range 3–7 THz.