Order-N photonic band structures for metals and other dispersive materials

We show how to calculate photonic band structures for idealized metals and other dispersive systems using an efficient order-N scheme. That is to say, we use a scheme where the calculation time scales linearly with the system size. The inverse dielectric function is treated as a simple pole. The met hod is applied to two simple periodic idealized metallic systems where it g ives results in close agreement with calculations made with other technique s. Further, the approach demonstrates excellent numerical stability within the limits we give. By generalizing to an inverse dielectric function expan ded as a series of poles, our method opens the way for efficient calculatio ns on complex structures containing a whole different class of material. [S 0163-1829(99)00204-0].