Chen YiJing, Yang Zheng, Wang LiuLi, Dong Wen, Chen Zhuo
Opt Express. 2023 Feb 13;31(4):5927-5939. doi: 10.1364/OE.482211.
We investigate the chiroptical responses of the hybrid systems consisting of metal-insulator-metal (MIM) gammadion arrays on top of a dielectric slab waveguide. We demonstrate that both the transverse magnetic (TM) and transverse electric (TE) waveguide modes could be coupled to the antisymmetric localized surface plasmon resonances (LSPRs) of the individual MIM-gammadions, leading to the formation of narrow hybrid waveguide-plasmon resonances (WPRs), of which the TM-WPR is less dependent while the TE-WPR is highly dependent on the handedness of the incident light. Associated with the excitation of the TE-WPRs, strong negative and positive circular dichroism (CD) peaks with high quality factors could be obtained on the short-wavelength and long-wavelength side of the LSPRs of the MIM-gammadion, respectively. Moreover, we show that the variation on either the lattice period or slab waveguide thickness allows for easily tuning the TE-WPRs based CD peaks over a relative wide spectral range. Our proposed hybrid system provides tunable and strong CD responses with narrow linewidth, which may have applications in chiral selective imaging, chiral plasmonic bio-sensing and spectroscopy.
我们研究了由介质平板波导顶部的金属-绝缘体-金属（MIM）伽马顿阵列组成的混合系统的手性光学响应。我们证明，横向磁（TM）和横向电（TE）波导模式都可以耦合到单个MIM-伽马顿的反对称局域表面等离子体共振（LSPR），从而导致形成窄的混合波导-等离子体共振（WPR），其中TM-WPR对入射光的手性依赖性较小，而TE-WPR则高度依赖于入射光的手性。与TE-WPR的激发相关，可以分别在MIM-伽马顿LSPR的短波长和长波长侧获得具有高品质因数的强负和正圆二色性（CD）峰。此外，我们表明，晶格周期或平板波导厚度的变化允许在相对较宽的光谱范围内轻松调谐基于TE-WPR的CD峰。我们提出的混合系统提供了具有窄线宽的可调谐且强的CD响应，这可能在手性选择性成像、手性等离子体生物传感和光谱学中具有应用。
