Highly Sensitive Sensor Structure Based on Sol-Gel Waveguide Films and Grating Couplers

The technologies of optical planar evanescent wave chemical and biochemical sensors require chemically resistant, high refractive index waveguide films having very good optical transmission properties. In this paper we present such two-compound SiOx:TiOy waveguide films fabricated by using the sol-gel method and the dip-coating technique. These films not only have high optical quality and low propagation losses but also an extremely high refractive index of >1.90 (λ = 632.8 nm). Further we demonstrate efficient and simple sensing structures, designed and fabricated based on these films. For this purpose, grating couplers with a period of Λ = 417 nm were fabricated on the interface between a waveguide film and cover using the single-step nanoimprint method. These sensing structures were tested as planar refractometers. The results of the theoretical analysis on the basis of which the structures were designed as well as results of their experimental characterization are presented in this work. Consequently, the relationship between parameters and the sensitivity of investigated sensing structures is discussed. As a result, the profitable properties of the designed grating coupler sensors are verified and excellent consistency between the results of the theoretical analysis and experimental results is achieved.

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Preparation of ultra-broadband antireflective coatings for amplifier blast shields by a sol–gel method

High Power Laser Science and Engineering ◽

10.1017/hpl.2017.28 ◽

2017 ◽

Vol 5 ◽

Cited By ~ 2

Author(s):

Huai Xiong ◽

Bin Shen ◽

Zhiya Chen ◽

Xu Zhang ◽

Haiyuan Li ◽

...

Keyword(s):

Refractive Index ◽

Sol Gel ◽

High Refractive Index ◽

Dip Coating ◽

Scratch Resistance ◽

Fused Silica ◽

Antireflective Coating ◽

Antireflective Coatings ◽

Average Residual ◽

Low Refractive Index

A type of $\unicode[STIX]{x1D706}/4$–$\unicode[STIX]{x1D706}/4$ ultra-broadband antireflective coating has been developed using modified low refractive silica and high refractive silica layers by a sol–gel dip coating method for amplifier blast shields of the Shen Guang II high power laser facility (SG-II facility). Deposition of the first layer (high refractive index silica) involves baking at $200\,^{\circ }\text{C}$ in the post-treatment step. The second layer (low refractive index, $n=1.20$) uses low refractive index silica sol modified by acid catalysis. Thermal baking at temperatures no less than $500\,^{\circ }\text{C}$ for 60 min offers chemical stability, ethanol scratch resistance, and resistance to washing with water. The average residual reflection of dual-side-coated fused silica glass was less than 1% in the spectral range from 450 to 950 nm. Transmission gain has been evaluated by taking into account angular light, and the results show that the transmission gain increases with increasing light incidence. Even at $60^{\circ }$, the transmission spectrum of the broadband antireflective coating effectively covered the main absorption peak of Nd:glass.

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Mode Sensitivity Exploration of Silica–Titania Waveguide for Refractive Index Sensing Applications

Sensors ◽

10.3390/s21227452 ◽

2021 ◽

Vol 21 (22) ◽

pp. 7452

Author(s):

Muhammad A. Butt ◽

Andrzej Kaźmierczak ◽

Cuma Tyszkiewicz ◽

Paweł Karasiński ◽

Ryszard Piramidowicz

Keyword(s):

Refractive Index ◽

High Performance ◽

Near Infrared ◽

Sol Gel ◽

Cost Effective ◽

Dip Coating ◽

Infrared Wavelength ◽

Refractive Index Sensing ◽

Sensing Applications ◽

Coating Method

In this paper, a novel and cost-effective photonic platform based on silica–titania material is discussed. The silica–titania thin films were grown utilizing the sol–gel dip-coating method and characterized with the help of the prism-insertion technique. Afterwards, the mode sensitivity analysis of the silica–titania ridge waveguide is investigated via the finite element method. Silica–titania waveguide systems are highly attractive due to their ease of development, low fabrication cost, low propagation losses and operation in both visible and near-infrared wavelength ranges. Finally, a ring resonator (RR) sensor device was modelled for refractive index sensing applications, offering a sensitivity of 230 nm/RIU, a figure of merit (FOM) of 418.2 RIU−1, and Q-factor of 2247.5 at the improved geometric parameters. We believe that the abovementioned integrated photonics platform is highly suitable for high-performance and economically reasonable optical sensing devices.

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Changes of thickness and refractive index of silica sol-gel film by dip coating process

High Power Laser and Particle Beams ◽

10.3788/hplpb20142607.72005 ◽

2014 ◽

Vol 26 (7) ◽

pp. 72005

Author(s):

张日东 Zhang Ridong ◽

严鸿维 Yan Hongwei ◽

吕海兵 Lü Haibing ◽

张尽力 Zhang Jinli ◽

晏良宏 Yan Lianghong ◽

...

Keyword(s):

Refractive Index ◽

Sol Gel ◽

Dip Coating ◽

Silica Sol ◽

Coating Process ◽

Gel Film

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Sol–Gel Derived Transparent Zirconium-Phenyl Siloxane Hybrid for Robust High Refractive Index LED Encapsulant

ACS Applied Materials & Interfaces ◽

10.1021/am500315y ◽

2014 ◽

Vol 6 (5) ◽

pp. 3115-3121 ◽

Cited By ~ 33

Author(s):

Yong Ho Kim ◽

Jun-Young Bae ◽

Jungho Jin ◽

Byeong-Soo Bae

Keyword(s):

Refractive Index ◽

Sol Gel ◽

High Refractive Index

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Ellipsometric Imaging of Drying Sol-Gel Films

MRS Proceedings ◽

10.1557/proc-121-731 ◽

1988 ◽

Vol 121 ◽

Cited By ~ 10

Author(s):

Alan J. Hurd ◽

C. Jeffrey Brinker

Keyword(s):

Refractive Index ◽

Sol Gel ◽

Dip Coating ◽

Drying Process ◽

Imaging Ellipsometry ◽

Withdrawal Velocity ◽

Coated Film ◽

Sol Gel Films ◽

Physical And Chemical ◽

Dip Coated Films

ABSTRACTAlthough controlled dip-coating is an established way to apply high quality uniform coatings, the details of the coating and drying process have not been deeply studied. Depending on the physical and chemical state of the sol and the parameters of dipping (dipping angle and speed), a variety of thicknesses and porosities can be achieved [1]. For optical coatings, the refractive index and optical thickness can thereby be controlled.We have developed a method to view the drying front of a dip-coated film using broad beam ellipsometry [2], or “ellipsometric imaging.” In dip-coated films we take full advantage of the fact that a steady state is quickly reached where the drying line velocity matches the withdrawal velocity; however, the technique might also be used in unsteady situations such as spin coating. Imaging ellipsometry makes it possible to measure the refractive index and thickness profiles of both wet and dry films point-by-point in an entire image at once. These profiles provide important clues as to the relative importance of gravity, evaporation and other phenomena.

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The Influencing Factors for the Thickness of Silica Sol-Gel Film by the Dip Coating Process

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.597.165 ◽

2014 ◽

Vol 597 ◽

pp. 165-169

Author(s):

Jie Hong Lei ◽

Ri Dong Zhang

Keyword(s):

Thin Films ◽

Surface Roughness ◽

Refractive Index ◽

Sol Gel ◽

Dip Coating ◽

Silica Sol ◽

Coating Process ◽

Power Functions ◽

Withdrawal Speed ◽

Gel Film

The porous sol-gel silica thin films were prepared on silicon substrate by the dip coating process. The surface roughness and microstructure of the film was measured by optical microscopy and AFM .Coating thickness and refractive index were measured by ellipsometry method. Influence of withdrawal speed and concentration of colloid was investigated for the thickness of silica. The relation of the thickness and withdrawal speed was fitted by the linear and power functions, and the results were analyzed and compared. It was found that the films with the same thickness prepared by different concentrations of colloid have different refractive indexes. The experimental results indicated that the thickness and refractive index of the film can be controlled by changing the withdrawal speed and colloid concentration.

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Thermally stable transparent sol–gel based active siloxane–oligomer materials with tunable high refractive index and dual reactive groups

RSC Advances ◽

10.1039/c6ra13164f ◽

2016 ◽

Vol 6 (75) ◽

pp. 70825-70831 ◽

Cited By ~ 8

Author(s):

Mei Chen ◽

Guoyan Zhang ◽

Xiao Liang ◽

Wanshu Zhang ◽

Le Zhou ◽

...

Keyword(s):

Refractive Index ◽

Sol Gel ◽

High Refractive Index ◽

Thermally Stable ◽

Transparent Film ◽

Reactive Groups ◽

Optical Applications

A novel active silicone–oligomers used as chemical intermediates in optical applications were synthesized and one of their derivatives, a transparent film with high refractive index, were presented.

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Sol-Gel Pzt Films for Optical Waveguides

MRS Proceedings ◽

10.1557/proc-243-533 ◽

1991 ◽

Vol 243 ◽

Cited By ~ 7

Author(s):

S.L. Swartz ◽

S.D. Ramamurthi ◽

J. R. Busch ◽

V.E. Wood

Keyword(s):

Refractive Index ◽

Optical Waveguides ◽

Sol Gel ◽

Optical Loss ◽

Ferroelectric Thin Film ◽

Thin Film Deposition ◽

Optical Quality ◽

Film Deposition ◽

Pzt Films ◽

Degree Of Orientation

AbstractSol-gel processing is a candidate ferroelectric thin-film deposition method for electronic and electro-optic applications. At Battelle, sol-gel PbTiO3 and Pb(Zr,Ti)O3 films have been prepared on sapphire and single-crystal SrTiO3 substrates. Films deposited and annealed on sapphire substrates are crystalline with the perovksite structure and minimal crystallographic orientation, whereas films deposited on isostructural and lattice-matched SrTiO3 substrates exhibit a high degree of orientation. Guided-mode refractive index measurements were made using a single-prism method and film indices were computed. Refractive index values measured for PbTiO3 films (n = 2.58) and PZT films (n = 2.50) were slightly lower than values expected on the basis of bulk measurements. In double-prism experiments, optical wavcguiding was achieved over distances up to 10 mm in oriented PZT films on [100] SrTiO3substrates. Optical loss of 19 dB/cm was measured on one of these film samples. Such films, given requisite improvement in optical quality, may be suitable for useful optical waveguide devices. An approach is presented for the integration of ferroelectric waveguides onto silicon and/or GaAs substrates.

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