scholarly journals Discrimination of Bulk and Surface Refractive Index Change in Plasmonic Sensors with Narrow Bandwidth Resonance Combs

ACS Sensors ◽  
2021 ◽  
Author(s):  
Fu Liu ◽  
Xuejun Zhang ◽  
Kaiwei Li ◽  
Tuan Guo ◽  
Anatoli Ianoul ◽  
...  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guangzhong Ma ◽  
Runli Liang ◽  
Zijian Wan ◽  
Shaopeng Wang

AbstractQuantification of molecular interactions on a surface is typically achieved via label-free techniques such as surface plasmon resonance (SPR). The sensitivity of SPR originates from the characteristic that the SPR angle is sensitive to the surface refractive index change. Analogously, in another interfacial optical phenomenon, total internal reflection, the critical angle is also refractive index dependent. Therefore, surface refractive index change can also be quantified by measuring the reflectivity near the critical angle. Based on this concept, we develop a method called critical angle reflection (CAR) imaging to quantify molecular interactions on glass surface. CAR imaging can be performed on SPR imaging setups. Through a side-by-side comparison, we show that CAR is capable of most molecular interaction measurements that SPR performs, including proteins, nucleic acids and cell-based detections. In addition, we show that CAR can detect small molecule bindings and intracellular signals beyond SPR sensing range. CAR exhibits several distinct characteristics, including tunable sensitivity and dynamic range, deeper vertical sensing range, fluorescence compatibility, broader wavelength and polarization of light selection, and glass surface chemistry. We anticipate CAR can expand SPR′s capability in small molecule detection, whole cell-based detection, simultaneous fluorescence imaging, and broader conjugation chemistry.


1990 ◽  
Vol 29 (3) ◽  
pp. 191 ◽  
Author(s):  
Takeshi Kato ◽  
Hiroaki Inoue ◽  
Yasushi Takahashi ◽  
Koji K. Ishida

1989 ◽  
Vol 157 ◽  
Author(s):  
T. Bremer ◽  
P.R. Ashley ◽  
R. Irmscher ◽  
Ch. Buchal

ABSTRACTSingle crystalline substrates of LiNb03 have been implanted with 48Ti ions at 200 keV and doses up to 4 × 1017 cm−2. The implants have been performed at wafer temperatures of 77 K, 300 K and 620 K. Immediate subsequent processing at 1273 K in wet oxygen ambient led to good epitaxial regrowth at all doses, if sufficient time was allowed. The maximum observed extraordinary refractive index change after regrowth Δne=0.04, indicating a solubility limit of 3.3×l021 Ti cm−3 corresponding to 18 % of Nb5+ replaced by Ti4+.


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