Self-healing Bessel-Gaussian beam generation based on multimode interference effect

Two typed Bessel-Gaussian beams with good non-diffraction and self-healing properties have been generated by using tapered hollow tubes with double layers. The evolution process of light propagation in the tapered hollow tube cavity is studied theoretically. The theoretically analysis and simulation results show that the Bessel-Gaussian beam generation is due to the multimode interference. Two typed Bessel-Gaussian beams are generated by changing the inner layer thickness of such hollow tubes, which both experiences autofocusing at the output port and evolve into Bessel-Gaussian beams. The effect of single and multiple silica particles on their self-healing performance has also been analyzed, which has a good property for ultrafast laser micromachining.