We report the experimental demonstration of tunable stop gap in the visible wavelength region by changing the angle of incidence of light. The width and peak reflectance of the stop gap do not change till an angle of incidence of 45°. For angle of incidence greater than 45°, new diffraction resonances appear in the reflectance spectra. At 55° incidence, the stop band split into to two peaks with equal reflected intensity. This multiple Bragg diffraction is in good