The combined optical and magnetic properties of magneto-plasmonic nanoparticles makes them ideal candidates for various applications in biomedical fields. In the present work, the optical properties of Ni–Ag and Ni–Au bimetallic alloy nanoparticles with varying sizes 20, 30, 40, 50, and 60 nm of spherical and aspect ratio 2, 3, and 4 of non-spherical nanostructures are studied by the discrete dipole approximation method in the water surrounding medium. Moreover, optical absorption spectra are studied to see the effect of polarization and different alloy compositions. The optical spectra is observed in the range of 371–1280 nm wavelengths and merged in visible-near-infrared region on the electromagnetic spectrum. The result shows that absorption spectra of bimetallic alloy nanoparticles can be well tuned by changing the particle size, aspect ratio’s, shapes, and compositions. Furthermore, Ni–Au nanoparticles have enrich optical absorption spectra as compared to Ni–Ag bimetallic nanoparticles. Our study provides a way to analyze and broaden the applications of bimetallic alloy nanoparticles in optical imaging, biomedical field, and therapeutics.

中文翻译：

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Ni-Ag 和 Ni-Au 纳米粒子在磁等离子体纳米结构中的可调光学特性

磁等离子体纳米粒子的光学和磁性相结合，使其成为生物医学领域各种应用的理想候选者。在目前的工作中，具有不同尺寸 20、30、40、50 和 60 nm 的球形和长宽比为 2、3 和 4 的非球形纳米结构的 Ni-Ag 和 Ni-Au 双金属合金纳米粒子的光学性质是水环境介质中离散偶极子近似法研究。此外，研究了光吸收光谱以观察偏振和不同合金成分的影响。在 371-1280 nm 波长范围内观察到光谱，并在电磁光谱的可见-近红外区域合并。结果表明，通过改变粒径可以很好地调节双金属合金纳米粒子的吸收光谱，纵横比、形状和成分。此外，与 Ni-Ag 双金属纳米粒子相比，Ni-Au 纳米粒子具有丰富的光学吸收光谱。我们的研究提供了一种分析和拓宽双金属合金纳米粒子在光学成像、生物医学领域和治疗学中的应用的方法。