Complex diamond lattice with wide band gaps in the visible range prepared by holography using a material with a low index of refraction

A holographic method was proposed to fabricate complex diamond lattice using materials with low refractive index. By this method, very wide band gaps were obtained experimentally. The width of the band gaps reached 260 nm; the ratio between the width and the central wavelength of the gaps reached 50%. Also, a common gap was observed in the range of 150° of incident angle in [1 1 1] plane at all orientations. This kind of complex-diamond lattice is greatly beneficial for obtaining complete band gaps.