Wang Yu-Jui, Dai Chi-An, Li Jia-Han
Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
Polymers (Basel). 2019 Mar 6;11(3):431. doi: 10.3390/polym11030431.
Core-shell microspheres have been applied in various research areas and, in particular, they are used in the generation of photonic nanojets with suitable design for photonic applications. The photonic nanojet is a narrow and focused high-intensity light beam emitting from the shadow-side of microspheres with tunable effective length, thus enabling its applications in biosensing technology. In this paper, we numerically studied the photonic nanojets brought about from biocompatible hydrogel core-shell microspheres with different optical properties. It was found that the presence of the shell layer can significantly affect the characteristics of the photonic nanojets, such as the focal distance, intensity, effective length, and focal size. Generally speaking, the larger the core-shell microspheres, the longer the focal distance, the stronger the intensity, the longer the effective length, and the larger the focal size of the generated photonic nanojets are. The numerical simulations of the photonic nanojets from the biocompatible core-shell microspheres on a Klarite substrate, which is a classical surface-enhancing Raman scattering substrate, showed that the Raman signals in the case of adding the core-shell microspheres in the system can be further enhanced 23 times in water and 108 times in air as compared in the case in which no core-shell microspheres are present. Our study of using tunable photonic nanojets produced from the biocompatible hydrogel core-shell microspheres shows potential in future biosensing applications.
核壳微球已应用于各个研究领域，特别是在光子应用的合适设计中用于产生光子纳米射流。光子纳米射流是一种从微球阴影侧发射的狭窄且聚焦的高强度光束，其有效长度可调，从而使其能够应用于生物传感技术。在本文中，我们对具有不同光学性质的生物相容性水凝胶核壳微球产生的光子纳米射流进行了数值研究。结果发现，壳层的存在会显著影响光子纳米射流的特性，如焦距、强度、有效长度和焦斑尺寸。一般来说，核壳微球越大，产生的光子纳米射流的焦距越长、强度越强、有效长度越长且焦斑尺寸越大。在经典的表面增强拉曼散射基底Klarite上对生物相容性核壳微球产生的光子纳米射流进行的数值模拟表明，与不存在核壳微球的情况相比，在系统中添加核壳微球时，水中的拉曼信号可进一步增强23倍，空气中可增强108倍。我们对利用生物相容性水凝胶核壳微球产生的可调谐光子纳米射流的研究显示了其在未来生物传感应用中的潜力。
