TY - JOUR T1 - Negative refraction, subwavelength focusing and beam formation by photonic crystals A1 - Ozbay, E. A1 - Aydin, K. A1 - Bulu, I. A1 - Guven, K. JA - J of Physics D Y1 - 2007 VL - 40 SP - 2652 EP - 2658 ER -