An air-bridged, 120-nm-thick semiconductor slab with a two-dimensional (2D) square array of through holes on a 480 nm pitch (&Lgr;) was fabricated using selective wet etching techniques. The second order photonic resonances of the structure were studied by comparing broadband optical scattering data with numerical solutions of Maxwell’s equations. Features observed in these spectra over a 1200cm−1range, near 9500cm−1,indicate that the 2D texture splits the energy degeneracy of slab modes with propagation constants {±2&pgr;/&Lgr;,0} and {0,±2&pgr;/&Lgr;} by as much as 14&percent;. ©1997 American Institute of Physics.