Effective electronic response of a system of metallic cylinders

The electronic response of a composite consisting of aligned metallic cylinders in vacuum is investigated on the basis of photonic band structure calculations. The effective long-wavelength dielectric response function is computed as a function of the filling fraction. A spectral representation of the effective response is considered and the surface mode strengths and positions are analyzed. The range of validity of a Maxwell-Garnett--like approach is discussed and the impact of our results on absorption spectra and electron energy-loss phenomena is addressed.