High-efficiency generation of ultralong, tunable, high-order nondiffracting beams

Non-diffracting beams have presented significant utility across various fields for their unique properties of self-healing, anti-diffraction, and high-localized intensity distribution. We present a versatile and highly efficient method for generating high-order non-diffracting beams predicated on the Fourier transformation of polymorphic beams produced by the free lens with tunable shape. Based on the tunability of the digital free lens, we demonstrate the experimental generation of various long distance non-diffracting beams, including Bessel beams, polymorphic generalized non-diffracting beams, tilted non-diffracting beams, asymmetric non-diffracting beams, and specially structured beams generated by the superposition of Bessel beams. Our method achieves the efficiency of up to 16 times compared with complex beam shaping methods. The generated NDBs exhibit characteristics of extended propagation distance and high-quality intensity profiles consistent with the theoretical predictions. The proposed method is anticipated to find applications in laser processing, optical manipulation, and other fields.