Low-loss optical waveguides for the near ultra-violet and visible spectral regions with Al2O3 thin films from atomic layer deposition

Aslan, Mustafa; Webster, Nathan; Byard, Courtney; Pereira, Marcelo Barbalho; Hayes, C.M.; Wiederkehr, Rodrigo Sérgio; Mendes, Sergio B.

doi:10.1016/j.tsf.2010.03.011

Cited by 89 publications

(51 citation statements)

References 24 publications

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“…In previous works [23][24][25] we have described the overall design, fabrication, and application of a single-mode, electro-active, integrated optical waveguide (SM-EA-IOW) as a platform (see Fig. 1) for spectroelectrochemical investigations using optical impedance measurements of a particular type of redox event at a certain specific condition on the electrode interface.…”

Section: Introductionmentioning

confidence: 99%

Electron-Transfer Rate in Potential-Modulated Redox Reactions with Electro-Active Optical Waveguides

Han

Mendes

2017

ANAL. SCI.

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A novel methodology has been developed to determine electron-transfer rate in electrically driven redox reactions. Based on a widely adopted electrical circuit describing faradaic processes in an electrochemical cell, the approach uses a combination of impedance data from optical and electrical measurements that are simultaneously acquired in a spectroelectrochemical experiment. Once the consistency of our methodology was experimentally corroborated, it was put to practice for investigating electron-transfer rate of cytochrome c adsorbates at very low concentrations on an indium tin oxide electrode by using a highly sensitive, single-mode, electro-active, integrated optical waveguide platform. Different surface densities of redox species on the electrode interface and different ionic strengths in the electrolyte solution were studied. Higher surface densities and higher ionic strengths are shown to slow down the electron-transfer process between the redox molecules and the working electrode.

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Section: Introductionmentioning

confidence: 99%

Electron-Transfer Rate in Potential-Modulated Redox Reactions with Electro-Active Optical Waveguides

Han

Mendes

2017

ANAL. SCI.

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“…The chemical precursors used for the ALD growth of the alumina film were tri-methyl-aluminum and water. Those precursors were alternatively injected inside the deposition chamber under vacuum to create a self-limiting monolayer for each cycle 40 . The deposition temperature in the reaction chamber was set at 250 °C, and 1690 cycles were required to reach the target thickness of approximately 178 nm.…”

Section: Methodsmentioning

confidence: 99%

Extension of the broadband single-mode integrated optical waveguide technique to the ultraviolet spectral region and its applications

Wiederkehr

Mendes

2014

Analyst

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We report here the fabrication, characterization, and application of a single-mode integrated optical waveguide (IOW) spectrometer capable of acquiring optical absorbance spectra of surface-immobilized molecules in the visible and ultraviolet spectral region down to 315 nm. The UV-extension of the single-mode IOW technique to shorter wavelengths was made possible by our development of a low-loss single-mode dielectric waveguide in the UV region based on an alumina film grown by atomic layer deposition (ALD) over a high quality fused silica substrate, and by our design/fabrication of a broadband waveguide coupler formed by an integrated diffraction grating combined with a highly anamorphic optical beam of large numerical aperture. As an application of the developed technology, we report here the surface adsorption process of bacteriochlorophyll a on different interfaces using its Soret absorption band centred at 370 nm. The effects of different chemical compositions at the solid/liquid interface on the adsorption and spectral properties of bacteriochlorophyll a were determined from the polarized UV-Vis IOW spectra acquired with the developed instrumentation. The spectral extension of the single-mode IOW technique into the ultraviolet region is an important advance as it enables extremely sensitive studies in key characteristics of surface molecular processes (e.g., protein unfolding and solvation of aromatic amino-acid groups under surface binding) whose spectral features are mainly located at wavelengths below the visible spectrum.

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“…In this study for fixed RI calculations, we assume that the prism is a BK7 glass with a triangular shape, and its RI is 1.51. The RIs of the sensor's layers were interpolated from the literature [13,14].…”

Section: Optical Propertiesmentioning

confidence: 99%

Sensitivity enhancement of coupled plasmon-waveguide resonance sensors with gold-silver-alumina layers

2012

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Coupling surface plasmon resonance mode to waveguide mode(s) by simply forming a dielectric layer on top of the metallic layer can improve the sensor's response to molecular variations. In this study, optimization of Coupled Plasmon -Waveguide Resonance (CPWR) sensors' layers to enhance their sensitivities is investigated. Optimizations of wavelength and thicknesses for highest sensitivities of the angularly interrogated CPWR sensors are accomplished with Fresnel equations and the full width half maximum calculations. Sensitivities are determined for three different film layer configurations that consist of: (I) gold-alumina, (II) silver-alumina, and (III) gold-silver-alumina layers. Optimum thicknesses and wavelength combinations for highest sensitivities are calculated in four steps in the spectral and the physical domains. The sensitivities averaged for the biolayer refractive index varying in the range of 1.330-1.385 are mapped around the optimum point of thickness combination as function of metallic and dielectric layer thicknesses at optimum wavelength. Results from our parametric study show that there is approximately 60-fold improvement in the sensitivity for optimized sensor design by comparing with a typical plasmonic sensor. The highest sensor's sensitivity is obtained at λ = 600 nm with the gold-silver-alumina layer combination. This study develops a detailed understanding of how both the dimensional and the spectral parameters affect the sensitivity of the CPWR sensors.

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Low-loss optical waveguides for the near ultra-violet and visible spectral regions with Al2O3 thin films from atomic layer deposition

Cited by 89 publications

References 24 publications

Electron-Transfer Rate in Potential-Modulated Redox Reactions with Electro-Active Optical Waveguides

Electron-Transfer Rate in Potential-Modulated Redox Reactions with Electro-Active Optical Waveguides

Extension of the broadband single-mode integrated optical waveguide technique to the ultraviolet spectral region and its applications

Sensitivity enhancement of coupled plasmon-waveguide resonance sensors with gold-silver-alumina layers

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