National Cheng Kung University, Mechanical Engineering Department, Tainan, Taiwan.
National Cheng Kung University, Mechanical Engineering Department, Tainan, TaiwanbNational Cheng Kung University, Advanced Optoelectronic Technology Center, Tainan, Taiwan.
J Biomed Opt. 2017 Apr 1;22(4):47002. doi: 10.1117/1.JBO.22.4.047002.
A surface plasmon resonance (SPR)-enhanced method is proposed for measuring the circular dichroism (CD), circular birefringence (CB), and degree of polarization (DOP) of turbid media using a Stokes–Mueller matrix polarimetry technique. The validity of the analytical model is confirmed by means of numerical simulations. The simulation results show that the proposed detection method enables the CD and CB properties to be measured with a resolution of 10 ? 4 refractive index unit (RIU) and 10 ? 5 ?? RIU , respectively, for refractive indices in the range of 1.3 to 1.4. The practical feasibility of the proposed method is demonstrated by detecting the CB/CD/DOP properties of glucose–chlorophyllin compound samples containing polystyrene microspheres. It is shown that the extracted CB value decreases linearly with the glucose concentration, while the extracted CD value increases linearly with the chlorophyllin concentration. However, the DOP is insensitive to both the glucose concentration and the chlorophyllin concentration. Consequently, the potential of the proposed SPR-enhanced Stokes–Mueller matrix polarimetry method for high-resolution CB/CD/DOP detection is confirmed. Notably, in contrast to conventional SPR techniques designed to detect relative refractive index changes, the SPR technique proposed in the present study allows absolute measurements of the optical properties (CB/CD/DOP) to be obtained.
提出了一种基于表面等离子体共振（SPR）增强的方法，利用斯托克斯-穆勒矩阵偏振技术测量混浊介质的圆二色性（CD）、圆双折射（CB）和偏振度（DOP）。通过数值模拟验证了分析模型的有效性。模拟结果表明，所提出的检测方法能够以 10-4 折射率单位（RIU）和 10-5 RIU 的分辨率分别测量 CD 和 CB 特性，折射率范围为 1.3 至 1.4。通过检测含有聚苯乙烯微球的葡萄糖-叶绿素复合样品的 CB/CD/DOP 特性，证明了所提出方法的实际可行性。结果表明，提取的 CB 值随葡萄糖浓度呈线性下降，而提取的 CD 值随叶绿素浓度呈线性增加。然而，DOP 对葡萄糖浓度和叶绿素浓度均不敏感。因此，证实了所提出的 SPR 增强斯托克斯-穆勒矩阵偏振法在高分辨率 CB/CD/DOP 检测方面的潜力。值得注意的是，与旨在检测相对折射率变化的传统 SPR 技术相比，本研究中提出的 SPR 技术允许对光学特性（CB/CD/DOP）进行绝对测量。
