Remote Sensing and Sensors|2 Article(s)
Ultrasensitive biosensors based on long-range surface plasmon polariton and dielectric waveguide modes
Leiming Wu, Jun Guo, Hailin Xu, Xiaoyu Dai, and Yuanjiang Xiang
An ultrasensitive biosensor based on hybrid structure and composed of long-range surface plasmon polariton (LRSPP) and dielectric planar waveguide (PWG) modes is proposed. Both PWG and LRSPP modes have strong resonances to form strong coupling between the two modes, and the two modes can couple to enhance sensitivityof sensors. In the hybrid structure, PWG is composed of cytop–Si–cytop multilayers and the LRSPP configuration is composed of cytop–metal–sensing medium multilayer slabs. The highest imaging sensitivities of 2264 and 3619 RIU?1 were realized in the proposed sensors based on Au and Al-monolayer graphene, respectively, which are nearly 1.2 and 1.9 times larger than the 1910 RIU?1 sensitivity of the conventional LRSPR sensor (LRSPP sensor). Moreover, it is demonstrated that the PWG-coupled LRSPP biosensor is applicable to the sensing medium, with refractive index in the vicinity of 1.34.of Guangdong Province (2016B050501005); Science and Technology Project of Shenzhen (JCYJ20140828163633996, JCYJ20150324141711667); Natural Science Foundation ofSZU (201452, 201517, 827-000051, 827-000052, 827-000059).
Photonics Research
  • Publication Date: Nov. 15, 2016
  • Vol. 4, Issue 6, 06000262 (2016)
Enhanced magneto-optical Kerr effect and index sensitivity in Au/FexCo1-x magnetoplasmonic transducers
Haipeng Lu, Chuan Liu, Jun Qin, Chuangtang Wang, Yan Zhang, Longjiang Deng, and Lei Bi
Magnetoplasmonic sensors are attractive candidates for ultrasensitive chemical and biomedical sensor applications. A variety of ferromagnetic metal thin films have been used for magnetoplasmonic device applications, yet the dependence of sensor performance on the optical and magneto-optical properties of ferromagnetic metal materials has been rarely studied. In this work, we report the study of enhanced magneto-optical Kerr effect (MOKE) and sensing performance in Au/FexCo1?x bilayer magneto-optical surface plasmon resonance (MOSPR) transducers. The optical constants of FexCo1?x (x=0, 0.29, 0.47, 0.65, and 1) in a sputter-deposited Au/FexCo1?x device are characterized by the attenuated total internal reflection (ATR) method. FexCo1?x thin films show different MOKEs as a function of the chemical concentration, with the highest transverse MOKE signal observed in Fe0.7Co0.3. Index sensing performance is closely related to the material’s optical and magneto-optical constants. By studying the sensing performance in the parameter space of the Au/FexCo1?x bilayer thicknesses, the highest sensitivity is found to be 0.385 (theoretical) and 0.306 RIU?1 (experimental) in the Au/Fe0.7Co0.3 MOSPR devices. Our research highlights the influence of the optical properties of ferromagnetic material to device sensitivity in MOSPR transducers. The high sensitivity in Au/FexCo1?x MOSPR devices make these structures attractive candidates for chemical and biomedical sensing applications.
Photonics Research
  • Publication Date: Jun. 20, 2017
  • Vol. 5, Issue 5, 05000385 (2017)