The benefits of unusual dispersive properties of photonic crystals are often mitigated by unwanted phenomena like spatial broadening of propagating beams. This problem is usually faced using millimeter long conditioning regions to precompensate for beam spreading. A new approach is explored here to manage the strong diffraction of photonic superprisms without preconditioning regions. Unconventional photonic crystal lattice cells are engineered using plane wave expansion calculations, and two photonic crystals having both positive dispersions but diffraction properties of opposite signs are selected. Light propagation in the combined photonic structure is studied using finite difference time domain simulation to validate the predicted dispersion accumulation and diffraction compensation approach.
展开▼
