Optical Modeling of a GaAs-Defect 1D Porous Silicon Photonic Crystal for High-Sensitivity γ-Ray Detection

Radiation sensors are vital for applications in medical diagnostics, environmental monitoring, and nuclear safety. However, conventional sensors often suffer from limited sensitivity and poor operational stability. In this work, we theoretically propose a high-performance γ-ray radiation sensor based on a one-dimensional porous silicon photonic crystal (1D PhC) incorporating a gallium arsenide (GaAs) defect layer and porous silicon layers infiltrated with chalcogenide glass compositions (Se ₇₀ S ₃₀ ₋ _x Sb _x ). The sensing mechanism is governed by monitoring the shift in defect mode resonance within the photonic bandgap as a function of γ-ray dose (0-500 kGy). Dose dependent refractive index variations in the irradiated chalcogenide glasses were modeled using Bruggeman’s effective medium approximation and analyzed through the transfer matrix method (TMM) simulations. The proposed design offers structural simplicity, cost efficiency, and outstanding sensitivity, highlighting its strong potential for practical deployment in nuclear radiation detection, medical imaging, and industrial monitoring applications.