Collimation Effect on THz Transmission Resonances in Metalized and Defected Photonic Structures

A photonic crystal resonator optically contacted with a metal film generates in the THz frequency range a system of sharp spikes of electromagnetic quenching matching the reflection spectra of a bore resonator. It was shown that the calculated angle-frequency map of reflection for a metalized polypropilene/air structure contains narrow lines of extraordinary transmission through the metal film. In this work, we found that sharp peaks of electromagnetic transmission can also be generated at certain conditions by the defect containing resonators. The effect depends essentially on the defect position and number of periods. A remarkable property of the considered resonators when a thin inclined line of transmission takes place against the backdrop of perfect reflection can serve as a ground effect in compact and reliable direction control devices and THz radiation collimating devices. Energy concentration and collimation effect in a metalized resonator structure fitted with a stochastic EMW reservoir was evaluated. Enhancement of THz radiation filtering based on peaks of resonant transmission was discussed.