Various photonic crystal structures fabricated by using a top-cut hexagonal prism

We demonstrate a holographic approach for the fabrication of large-area photonic crystal (PhC) microstructures by applying a single top-cut hexagonal prism (TCHP). The interference patterns of the beams from the TCHP are calculated. Various two-dimensional PhC structures are fabricated in photo-resist films. They include symmetrical hexagonal structures, the honey-comb structure and the hexagonal structure with skewed elliptical rods. The first structures come from six-beam and symmetrical three-beam interfering. The second structure appears when the beam is incident on the TCHP obliquely. The third structure is obtained when adjacent three beams or four beams are interfered. The period can be decreased to 285 nm. SPM observations of the PhCs provide the basis for measurement of their structural parameters. A good agreement is obtained for the measured structural parameters and calculated results for the PhCs. The photonic band gaps of the hexagonal symmetrical and honeycomb structures are derived by using the plane wave method. These results reveal that, by varying the number of split beams and the incident angle, using the single TCHP PhCs, different band gaps can be achieved.