In terahertz (THz) range, ultra-long non-diffraction Bessel beams have been theoretically and experimentally developed and consequently achieved significant advancements. Nevertheless, the balance between non-diffraction length and optical intensity is restricted and their applications have been limited in part due to their complication in access and operation, loss of energy and spectral bandwidth. In this work, a composite system composed of multiple lenses and axicon is presented to engender ultra-long terahertz Bessel beams. By manipulating the spatial relationships between various THz components, the delivery distance and non-diffraction length surpass 40cm and 2m respectively.
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