Wide-range and tunable diffraction management using 2D rectangular lattice photonic crystals

We propose that 2D rectangular lattice photonic crystals composed of dielectric rods can be utilized for wide-range and tunable diffraction management. The control of diffraction for a normally incident beam is achieved by either properly choosing the operating frequency or changing the refractive index of the dielectric rods. The convergent, collimated, and divergent beam behaviors corresponding to a wide range of diffraction are clearly illustrated using FDTD simulations. The tunability of diffraction around the frequency of super-collimation is also analyzed and demonstrated.