Enhanced superprism effect in symmetry reduced photonic crystals

We propose compact S-vector superprism providing broadband wavelength sensitivity within a/λ = 0.610-0.635, where "a" is the lattice constant, λ is the incident wavelength, and S denotes the Poynting vector. The reported configuration overcomes strong beam divergence and complex beam generation due to the self-collimation ability of the low symmetric primitive photonic crystal (PhC) cells. Analytical calculations of equi-frequency contours, photonic band structures, and group velocity dispersions are performed by solving Maxwell's equations and using the plane wave expansion method. Besides, finite-difference time-domain analyses are also conducted. The designed superprism induces large refracted angle variation for different frequencies when the incident angle is fixed: 4% change of incident frequencies results in approximately 40° deflected angle difference with a maximum 68.9° deflection angle inside the PhC. Meanwhile, for a fixed incident wavelength, a large output variation occurs if the incident angle is altered. Microwave experimental results are found to be in good agreement with the numerical analyses. The authors M.G. and H.K. gratefully acknowledge the financial support of the Scientific and Technological Research Council of Turkey (TUBITAK) with Project No. 115R036. H.K. also acknowledges the partial support of the Turkish Academy of Sciences.