Tunable Filter Based upon Thue–Morse Photonic Crystal Structures

Thue-Morse structures are quasicrystals that can provide omni-directional reflectance and light emission enhancement. Starting from a Thue–Morse structure made of alternating layers of air and InP, we analyze the effects of adding a defect to the structure and changing the incidence angle on the response of the device. In fact, we show that the resonance wavelength can be tuned by adequate control of the angle of incidence of the incoming electromagnetic wave. The modified device has nearly 100% transmissivity and quality factor above 3,000, with a total length of less than 3.449 μm. The device may find applications in optical switching and filtering.