Photonic Crystals: band gaps for photons!
Just like semiconductor crystals, which are periodic structures of atoms and molecules, display band gaps for electrons, photonic crystals, which are periodic structure of dielectrics, display band gaps for photons. Photons with energies within the photonic band gap of a photonic crystal cannot propagate through the material. They are either forced outside the photonic crystal or not allowed to enter the material. The periodic variation of dielectric constant within the material manipulates the propagation of photons through the material, resulting in many interesting phenomena. The wings of butterflies and many other insects are examples of natural photonic crystals that add beautiful colors to the nature. However, man-made photonic crystals are still in pre-mature stage. One of the important things in photonic crystal is to obtain a full photonic band gap, which means to obtain a sufficient overlap between the TE and TM band gaps. We are interested in understanding the physical properties of photonic crystal that influence the possibility of obtaining full band gap. In particular, we are involved in theoretical simulations for the same.