Broadening of Non-Transmission Band of Ultra-Narrow Band-Pass Filters Using Heterostructures

Transmission characteristics are studied for the hybrid structures combining defect and multiple heterostructures. It is shown that the non-transmission frequency range can be substantially enlarged and the phenomenon of narrow band-pass filter can be realized by adjusting the number, position and size of the defect. The theoretical and experimental results on heterostructures containing Ta₂O₅/SiO₂ multilayer films are presented. Withperfect non-transmission frequency range and high peak transmissivity, this structure opens a promising way to fabricate ultra-narrow band-pass filters with wide non-transmission frequency range.