Fuentes Omar, Del Villar Ignacio, Corres Jesus M, Matias Ignacio R
Institute of Smart Cities, Public University of Navarre, 31006, Pamplona, Spain.
Department of Telecommunications and Electronics, Pinar del Río University, Pinar del Río, CP, 20100, Cuba.
Sci Rep. 2019 Jun 20;9(1):8882. doi: 10.1038/s41598-019-45285-x.
The deposition of an indium oxide (InO) thin film on conventional planar waveguides (a coverslip and a glass slide) allows generating lossy mode resonances (LMR) by lateral incidence of light on the waveguide and by registering the optical spectrum in a spectrometer. This novel sensing system becomes an alternative to optical fibre, the substrate where LMR-based sensors have been developed so far, since it is easier to handle and more robust. An additional advantage is that cost effective waveguides, such as slides or coverslips, can be used in a platform that resembles surface plasmon resonance-based sensors in the Kretschmann configuration but without the need for a coupling prism and with the advantage of being able to generate TE and TM LMR resonances with metallic oxide or polymer thin films. The results are corroborated with simulations, which provide in-depth understanding of the phenomena involved in the sensing system. As a proof-of-concept for the optical platform, two refractometers were developed, one with low sensitivity and for a wide range of refractive indices, and the other with higher sensitivity but for a narrower refractive index range. The sensors presented here open up the path for the development of LMR-based chemical sensors, environmental sensors, biosensors, or even the generation of other optical phenomena with the deposition of multilayer structures, gratings or nanostructures, which is much easier in a planar waveguide than in an optical fibre.
在传统平面波导（盖玻片和载玻片）上沉积氧化铟（InO）薄膜，通过光在波导上的横向入射并在光谱仪中记录光谱，可产生损耗模式共振（LMR）。这种新型传感系统成为光纤的一种替代方案，因为到目前为止基于LMR的传感器都是在光纤这种衬底上开发的，而该平面波导更易于操作且更坚固耐用。另一个优点是，在一个类似于Kretschmann配置的基于表面等离子体共振的传感器平台中，可以使用诸如载玻片或盖玻片等经济高效的波导，且无需耦合棱镜，并且能够通过金属氧化物或聚合物薄膜产生TE和TM LMR共振。模拟结果证实了这些结果，其提供了对传感系统中所涉及现象的深入理解。作为该光学平台的概念验证，开发了两种折射仪，一种灵敏度低但适用于较宽的折射率范围，另一种灵敏度较高但适用于较窄的折射率范围。本文介绍的传感器为基于LMR的化学传感器、环境传感器、生物传感器的开发开辟了道路，甚至通过多层结构、光栅或纳米结构的沉积来产生其他光学现象，这在平面波导中比在光纤中要容易得多。
