Tunable photonic crystals with semiconducting constituents

Summary form only given. We propose that the photonic band structure of semiconductor-based photonic crystals can be made tunable if the free-carrier density is sufficiently high. In this case, the dielectric constant of the semiconductor is frequency-dependent, and it also depends on the temperature T and the impurity concentration N through the plasma frequency. Then the photonic band structure is very sensitive to temperature and doping; it is even possible to obliterate a photonic gap.