Holographic lithography coupled with the nonlinear response of photoresist to the exposure is adopted to fabricate porous photoresist(PR)mask.Conventional dot PR mask is also generated,and both pattes are transferred into a underlying GaAs substrate by the optimal dry etching process to obtain tapered subwavelength crossed gratings(SWCGs)to mimic the moth-eye structure.In comparison of the experiment and simulation,the closely-packed pseudo-rhombus-shaped GaAs SwcGs resulting from the porous mask outperforms the conical counterpart which comes from the dot mask.and achieves a reported lowest mean spectral reflectance of 1.1%.