We fabricated a highly sensitive layered structure of organic molecules and studied the influence of polarization of the external electromagnetic (EM) wave on the surface plasmon resonance response from the layered structure. The layered structure was formed by depositing a self-assembled monolayer (SAM) of mercaptoundecanoic acid (MUA) followed by a single layer of Langmuir-Schaefer (LS) film of traditional calamitic liquid crystal molecule, 4-octyl-4-biphenylcarbonitrile (8CB). The SAM of MUA was found to be non-responsive towards the change in resonance angle (RA) of surface plasmon resonance (SPR) due to the change in polarization of the external EM wave. However, such layer provides a soft-surface platform for the single layer of 8CB molecules which gets perturbed locally due to the incidence of the external EM wave. We obtained an oscillatory modulation of the change in RA due to the change in polarization angle of the EM wave with respect to the plane of incidence. The magnitude of sensitivity was found to be ∼4 milli/ angle of polarization of the external EM wave. This study strongly suggests that sensitivity of a SPR-based sensor can be controlled by altering the linear state of polarization of the incident external EM wave.

我们制造了一种高度敏感的有机分子层状结构，并研究了外部电磁 (EM) 波的极化对层状结构的表面等离子体共振响应的影响。通过沉积巯基十一烷酸（MUA）的自组装单层（SAM）和传统棒状液晶分子的单层Langmuir-Schaefer（LS）膜形成层状结构，4-octyl-4-biphenylcarbonitrile (8CB)。由于外部 EM 波的极化变化，发现 MUA 的 SAM 对表面等离子体共振 (SPR) 的共振角 (RA) 的变化无响应。然而，这种层为单层 8CB 分子提供了一个软表面平台，由于外部 EM 波的入射而局部扰动。由于 EM 波的偏振角相对于入射平面的变化，我们获得了 RA 变化的振荡调制。灵敏度的幅度被发现是〜外部电磁波的偏振4毫/角度。这项研究强烈表明，基于 SPR 的传感器的灵敏度可以通过改变入射外部 EM 波的线性极化状态来控制。