In order to carry out precise measurements of the thickness of a dielectric layer deposited on a metal surface, we have introduced an ellipsometric measurement technique (EMT) to the modified Otto's configuration (MOC) that is used for observing surface plasmon resonance (SPR). For that purpose, we have measured the thickness of the Au layer by the EMT at four different locations on an elliptic fringe pattern obtained from the MOC basing on a four-layer structure model: prism (BK7)-air-Ausubstrate (BK7). Then, we have measured that of a TiO(2) layer deposited on the Au layer by the EMT basing on a five-layer structure model: prism (BK7)-air-TiO(2)-Au-substrate (BK7). We have found experimentally that the combination of EMT and MOC is effective for measuring the thickness of the dielectric layer on the metal.
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http://dx.doi.org/10.1364/OE.18.014480 | DOI Listing |
Nanophotonics
March 2024
Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
As a non-destructive and rapid technique, optical scatterometry has gained widespread use in the measurement of film thickness and optical constants. The recent advances in deep learning have presented new and powerful approaches to the resolution of inverse scattering problems. However, the application of deep-neural-network-assisted optical scatterometry for nanostructures still faces significant challenges, including poor stability, limited functionalities, and high equipment requirements.
View Article and Find Full Text PDFSci Rep
November 2024
Institut für Hochfrequenztechnik, Technische Universität Braunschweig, Brunswick, 38106, Germany.
In this work, we report on the application of the polarization modulated spectroscopic ellipsometry-based surface plasmon resonance method for sensitive detection of microorganisms in Kretschmann configuration. So far, rotating analyzer and single wavelength polarization modulation methods have widely been investigated for phase sensitive surface plasmon resonance measurement. In this study, a much simpler optical setup relying on fast electro-optic phase modulator crystals is introduced for bacteria detection.
View Article and Find Full Text PDFMolecules
September 2024
School of Civil Engineering, Liaoning Petrochemical University, Fushun 113001, China.
Poly(-isopropylacrylamide) (PNIPAM) offers a promising platform for non-invasive and gentle cell detachment. However, conventional PNIPAM-based substrates often suffer from limitations including limited stability and reduced reusability, which hinder their widespread adoption in biomedical applications. In this study, PNIPAM copolymer films were formed on the surfaces of glass slides or silicon wafers using a two-step film-forming method involving coating and grafting.
View Article and Find Full Text PDFEnergy Adv
October 2024
BCMaterials, Basque Center for Materials, Applications, and Nanostructures UPV/EHU Science Park 48940 Leioa Spain
Unraveling the knowledge of the complex refractive index and photophysical properties of the perovskite layer is paramount to uncovering the physical process that occurs in a perovskite solar cell under illumination. Herein, we probed the optical and photophysical properties of FAPbI (FAPI) and CsFAPbI (CsFAPI) thin films deposited from pre-synthesized powder, by the spectroscopic ellipsometer and time-resolved fluorescence spectra. We determined the complex refractive index of perovskite films by fitting the measured spectroscopic ellipsometer data with the three-oscillator Tauc-Lorentz (T-L) model.
View Article and Find Full Text PDFAdv Sci (Weinh)
October 2024
Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
Measurements of the refractive index of liquids are in high demand in numerous fields such as agriculture, food and beverages, and medicine. However, conventional ellipsometric refractive index measurements are too expensive and labor-intensive for consumer devices, while Abbe refractometry is limited to the measurement at a single wavelength. Here, a new approach is proposed using machine learning to unlock the potential of colorimetric metasurfaces for the real-time measurement of the dispersive refractive index of liquids over the entire visible spectrum.
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