This paper proposes a novel multi-beam lithography method for fabricating nanoscale photonic crystals without cracking. Using multi-beam ultrafast laser processing and etching, parallel channels with subwavelength gaps are created in yttrium aluminum garnet (YAG) crystals. The gap width is controlled at the nanoscale by adjusting phase holograms, enabling the creation of complex channel array distributions. Optical gratings with varying periods are fabricated, demonstrating the method's efficiency in producing nanostructures with controllable gaps for integrated photonics applications.
