بررسي، مطالعه و شبيه سازي لايه‌هاي نازك ناهمگن براي سامانه‌هاي پادبازتاب در ناحيه ي مرئي

Investigation, Analysis, an‎d Simulation of Inhomogeneous Thin Films for Antireflection Systems in the Visible Region

فيزيك

In this thesis, the design an‎d simulation of dielectric antireflection coatings based on inhomogeneous thin films in the visible spectral region are investigated. The main objective is to eva‎luate the capability of refractive index gradient structures as a suitable alternative to conventional homogeneous an‎d multilayer antireflection coatings. The optical behavior of these structures is analyzed using the transfer matrix method, in which continuous inhomogeneous layers are approximated by a stack of equivalent homogeneous sublayers. Cosine refractive index profiles are employed to model inhomogeneity, an‎d the effects of substrate type, dielectric material pairs, an‎d the number of oscillation cycles of the refractive index profile on the antireflection response are examined. All numerical simulations an‎d optimizations are carried out in the Python programming environment. Ran‎dom search an‎d simulated annealing algorithms are implemented to optimize the design parameters of the coating structures. The results indicate that gradient inhomogeneous coatings can provide smooth an‎d well-controlled spectral behavior without increasing the number of discrete layers. From a design perspective, the gradual variation of the refractive index reduces sensitivity to thickness errors an‎d interfacial discontinuities, enabling continuous engineering of optical properties. Accordingly, inhomogeneous dielectric thin films can be considered as a practical an‎d effective alternative to conventional homogeneous antireflection coatings for optical an‎d photonic systems. Keywords:

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