The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 25 4 2026 02 20 Design of a passband optical filter in a one-dimensional photonic crystal based on a reconfigurable Sb2S3 nanodefect Design of a passband optical filter in a one-dimensional photonic crystal based on a reconfigurable Sb2S3 nanodefect 517 535 3755 10.47176/ijpr.25.4.82168 FA Zahra Ehsanian Department of Atomic and Molecular Physics, Faculty of Science, University of Mazandaran, Babolsar, Iran Arezou Rashidi Department of Atomic and Molecular Physics, Faculty of Science, University of Mazandaran, Babolsar, Iran 0000-0001-5944-3226 Journal Article 2025 08 11 In this article, the optical response of a symmetric one-dimensional photonic crystal incorporating a central defect layer of Sb₂S₃ nanomaterial in the near-infrared region is simulated and analyzed using the transfer matrix method. The effects of the amorphous-to-crystalline phase transition of the defect layer, as well as variations in the incident angle of the incoming light, on the transmission characteristics of the structure in both TE and TM polarizations are investigated. The results show that the amorphous-to-crystalline phase transition of Sb₂S₃ induces a pronounced red shift in the defect mode wavelength, whereas increasing the incidence angle leads to a blue shift of both the photonic bandgap and the defect mode in both polarizations. For TE polarization, the defect mode linewidth decreases with increasing angle, resulting in a higher quality factor; however, for TM polarization, at angles close to the Brewster angle, the defect mode merges with the bandgap edge, leading to a degradation of the filter performance. The analysis of the transmittance difference between the two phases further reveals the high angular and polarization sensitivity of the structure. These findings confirm the strong potential of Sb₂S₃ for the design of angle-sensitive optical filters and reconfigurable photonic devices with spectral switching and modulation capabilities. In this article, the optical response of a symmetric one-dimensional photonic crystal incorporating a central defect layer of Sb₂S₃ nanomaterial in the near-infrared region is simulated and analyzed using the transfer matrix method. The effects of the amorphous-to-crystalline phase transition of the defect layer, as well as variations in the incident angle of the incoming light, on the transmission characteristics of the structure in both TE and TM polarizations are investigated. The results show that the amorphous-to-crystalline phase transition of Sb₂S₃ induces a pronounced red shift in the defect mode wavelength, whereas increasing the incidence angle leads to a blue shift of both the photonic bandgap and the defect mode in both polarizations. For TE polarization, the defect mode linewidth decreases with increasing angle, resulting in a higher quality factor; however, for TM polarization, at angles close to the Brewster angle, the defect mode merges with the bandgap edge, leading to a degradation of the filter performance. The analysis of the transmittance difference between the two phases further reveals the high angular and polarization sensitivity of the structure. These findings confirm the strong potential of Sb₂S₃ for the design of angle-sensitive optical filters and reconfigurable photonic devices with spectral switching and modulation capabilities. https://ijpr.iut.ac.ir/article_3755_cd3bbc2d7ca1bbdc055acf58609e6c24.pdf