Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 54: Photonische Kristalle III

HL 54.2: Vortrag

Dienstag, 8. März 2005, 15:15–15:30, TU P164

Focusing and negative group velocity in a planar array of dielectric rods — •Dan Davidov¹, Yair Neve-Oz¹, Yuval Saado¹, Michael Golosovsky¹, and Avri Frenkel² — ¹Racah Institute of Physics, Hebrew University of Jerusalem, 91904 Jerusalem, Israel — ²ANAFA Electromagnetic Solutions Ltd, P.O.B. 5301, Kiriat Bialik 27000, Israel

We suggest 2D photonic crystals (PC) consisting of a periodical array of dielectric rods in which array of point defects form a superlattice. The defects are made from different dielectric rods with different sizes and different dielectric constants. The distance between the defects is such that they are electromagnetically coupled to form coupled cavity propagating mode, CCM . This results in a defect band inside the photonic bandgap. Simulations using ANSOFT software demonstrate, at frequencies corresponding to the defect band, an extremely low group velocity in finite size PC and a negative group velocity in the band structure of infinite size PC. The above results are based on simulations. As a first step towards implementation, we have constructed a 2D photonic band gap material consisting of dielectric rods designed to operate in the mm wave range. In particular, we made from it a concave mirror and showed that in the frequency range corresponding to photonic stopband this mirror allows wave focusing with the spot size of 0.35 lambda. In this case simulations and experiments completely agree, so we are confident that a negative group velocity both in the microwave and in the infrared range can be realized using the CCM idea presented here.