Designing photonic devices that can manipulate and process light without altering the fabrication process is a longstanding challenge and crucial for many practical photonics applications. In particular, the reconfigurable photonic crystal (PhC) consists of a periodic array of dielectric, which adds additional freedom to tune the flow of light by strongly confining the light field. Herein, we numerically design and optimize a one-dimensional defect photonic crystal (1-D DPhC) and demonstrate a tunable absorption in the visible wavelength. The \(\hbox {Sb}_2\hbox {S}_3\) , a wide-band gap phase change material, is employed as a defect layer to tune the photonic bandgap and defect mode optical properties. A maximum change in absorption of 31% is achieved at 626 nm when the 10 nm \(\hbox {Sb}_2\hbox {S}_3\) defect layer switches its structure from an amorphous to a crystalline state in the PhC, corresponding to a resonance with a Q-factor of approximately 12,518. Moreover, the defect mode absorption exhibits a pronounced redshift of \(\Delta \lambda = 150\) nm from the visible to the near-infrared region as the defect layer thickness increases from 5 to 70 nm, highlighting the potential for tuning photonic responses across a broad spectral range. The optimized \(\hbox {Sb}_2\hbox {S}_3\) -based 1-D DPhC structure is polarization-independent and shows a blue shift of \(\Delta \lambda \) = 75 nm in an angle rotation of \(60^\circ \) . The temperature-dependent optical properties of \(\hbox {Sb}_2\hbox {S}_3\) during its amorphous-to-crystalline phase transition reveal a strong correlation between refractive index changes and enhanced absorption, demonstrating the robustness and adaptability of this PhC design for applications in tunable in-chip optical devices.
