Abstract
Optical tunneling is an effect extremely sensitive to wavelength changes. In this article, we use this effect to design a new type of biosensor. The tunneling effect is excited by long range surface plasmon resonance, the energy is concentrated in the sensing medium in the form of standing waves, which lead a very high wavelength sensitivity and quality factor. By using COMSOL for finite element analysis, for the sensor structure of (BK7/Cytop /Al2O3/Ag/Al2O3/sensing media/air), a quality factor of 10296 RIU-1 is achieved under angle modulation,a sensitivity of 170,000 nm/ RIUand a quality factor of 11333 RIU-1 are obtainedunder wavelength modulation. At the same time, the advantage of this structure is that there is no excessive requirement on the refractive index of the material, and a good sensing effect can be achieved even if the material is cheap and easy to prepare. After optimization, this structure is suitable for sensing media with a refractive index of 1.335-1.375, which can be applied to most liquid solutions.
Highlights
OVer time, optical biosensors have become more and more attractive because they can detect biomolecules quickly and in real time without pre-labeling, which can be used in explosive environments, are resistant to electromagnetic interference, and have biocompatibility
In order to improve the performance of the sensor and overcome these limitations, new SPR modes such as long-range surface plasmon resonance (LRSPR) [4], coupled plasma-waveguide resonance (CPWR) [5], and waveguide coupled SPR (WCSPR) [5] have been put forward
If the thickness of the low refractive index medium layer is less than the penetration depth of the evanescent wave, the light can break through the limit of total reflection and continue to propagate forward
Summary
OVer time, optical biosensors have become more and more attractive because they can detect biomolecules quickly and in real time without pre-labeling, which can be used in explosive environments, are resistant to electromagnetic interference, and have biocompatibility. Optical tunneling is a special phenomenon that was first paid attention to by Newton It refers to the ability of light waves (or photons) to pass through classically impenetrable material structures. If the thickness of the low refractive index medium layer is less than the penetration depth of the evanescent wave, the light can break through the limit of total reflection and continue to propagate forward. C. Bonazzola proposed that the maximum sensitivity mainly depends on the angle and polarization state of the incident light and the absorption characteristics of the third high-refractive-index dielectric layer [10]. Q. Jian used the optical tunneling effect to be extremely sensitive to changes in refractive index to make refractometers [11]. Compared with the sensor constructed based on the SPR principle under wavelength modulation, optical tunneling can achieve higher sensitivity and resolution.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
