OICC Press Journal of Theoretical and Applied Physics 2251-7235 6 1 2023 11 17 Investigation on the dependence of optical spectra of silver chiral nanostructures on shape, dimensions and incident light by discrete dipole approximation 10.1186/2251-7235-6-11 EN Fatemeh Abdi Department of Physics, University of Tehran OICC Author Unknown Hadi Savaloni School of Physics, College of Science, University of Tehran, North‑Kargar Street, Tehran, Iran 0000-0002-6836-106X Journal Article 2023 11 17 AbstractExtinction spectra of chiral silver nanostructures are calculated by means of Discrete Dipole Approximation (DDA). Dependence of Plasmonic peaks to both structural parameters of nanostructures and direction of the incident light are obtained. This dependence is investigated on variation of chiral dimensions, chiral shape and direction of incident light. We have observed a resonance peak of transverse mode (TM) for the extinction spectra of chiral structure at normal incidence. However, for oblique angle incident light, in addition to the TM mode, a longitudinal mode (LM) appears at longer wavelengths. The latter undergoes a shift to longer wavelengths with increasing the diameter of chirl arm. When the cross-section of chiral is changed to an oval this resonance peak disappears, while some other peaks appear at longer wavelengths that were not present for a chiral with circular cross-section. Extinction spectra of chiral nanostructure with different structural parameters and different rise angles (slanted chirals) showed dependence on the incident light direction.