Tunable photonic crystals with semiconducting constituents

We propose that the photonic band structure (PBS) of semiconductor-based ph otonic crystals (PCs) can be made tunable if the free-carrier density is su fficiently high. In this case, the dielectric constant of the semiconductor , modeled as epsilon(omega) = epsilon(0)(1 - omega(p)(2)/omega(2)), depends on the temperature T and on the impurity concentration N through the plasm a frequency omega(p). Then the PBS is strongly T and N dependent; it is eve n possible to obliterate a photonic band gap. This is shown by calculating the 2D PBS for PCs that incorporate either intrinsic InSb or extrinsic Ge.