Numerical and experimental analysis of Bessel beam properties based on continuous-wave terahertz radiation

Abstract

Terahertz imaging technology has been widely used in various fields. In continuous-wave terahertz imaging system, when the large size object is located at the unfocused position, Bessel beam with non-diffractive properties show its large depth of focus advantage over Gaussian beam. Bessel beam can be generated by the axicon, which has high conversion efficiency. The non-diffraction distance and the main lobe size of the Bessel beam depend on the parameters of the axicon and incident light wavelength. We analyzed that the influence on the axial two-dimensional intensity distribution of a zero-order Bessel beam by changing the axicon parameters and the incident Gaussian beam size. Experimentally, the axicon with different parameters were fabricated using different materials. Then the two-dimensional intensity distribution of the Bessel beam in the axial and transverse direction were recorded and analyzed. The experimental results is basically consistent with the theoretical ones.