Akademik Veri Yönetim Sistemi
IEEE Access, 2026 (SCI-Expanded, Scopus)
Dielectric metalenses have emerged as compact and versatile alternatives to conventional refractive optics, offering precise wavefront control through subwavelength-scale phase modulation. Their potential for integration in photonic systems is especially promising in the near-infrared spectral range, where applications in optical communication, imaging, and sensing are rapidly expanding. This study presents the design and numerical analysis of a germanium-based dielectric metalens operating at the optical-fiber telecommunication wavelength of 1550 nm. Despite the intrinsically lossy nature of germanium in the near-infrared regime, we demonstrate that efficient focusing can be achieved through careful phase engineering of subwavelength meta-atoms. The metalens consists of cylindrical germanium nanopillars placed on a low-index substrate and is designed to achieve a focal length of 1 mm. Rigorous coupled-wave analysis was employed to evaluate the transmission and phase-shifting characteristics of the meta-atoms over a range of geometrical parameters. A discrete set of resonant and non-resonant nanopillars was selected to provide full 0 to 2π phase coverage. To gain insight into the physical mechanisms of phase modulation, scattering efficiency and multipole decomposition analyses were conducted, revealing strong magnetic dipole resonances in specific configurations. The final metalens structure was assembled based on the extracted phase profile and analyzed using finite-difference time-domain simulations. The results show a focusing efficiency of 78.6% at the target wavelength and focal length, validating the potential of germanium as a CMOS-compatible material for compact and high-performance near-infrared nanophotonic devices.