Optical waveguide sensor using evanescent wave excitation of fluorescent dye in sol-gel glass

MacCraith, Brian D.; Ruddy, Vincent P.; Potter, Colin E; O’Kelly, Brendan C.; McGilp, J. F.

doi:10.1049/el:19910781

Cited by 128 publications

(53 citation statements)

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“…Fibres up to 1 m length were drawn 35 . These fibres were studied for pH sensing and as laser dye when appropriately doped by fluorescent molecules, viz., fluorescein and rhodamine-6G 36,37 The special network structure can be used in sound detection 40 . Porous silica films are also used as adsorbents, scaffolds for composite material synthesis, in separation technology 42 , and molecular and biological engineering 43 .…”

Section: Sol-gel Glasses Optical Fibres and Nanocomposite Materialsmentioning

confidence: 99%

“…Fibres up to 1 m length were drawn 35 . These fibres were studied for pH sensing and as laser dye when appropriately doped by fluorescent molecules, viz., fluorescein and rhodamine-6G 36,37 . Nanoparticles of semiconductors or metals have been widely investigated for applications in nonlinear optics 38 .…”

Section: Sol-gel Glasses Optical Fibres and Nanocomposite Materialsmentioning

confidence: 99%

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Sol-gel Technology for Sensor Applications

Chaudhury

Gupta

Gulia

2007

DSJ

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Sol-gel processes refer to the transition of predefined compositions of inorganic alkoxides precursors from liquid sol phase to solid gel phase. The phenomenon of sol-gel was known to mankind for more than 150 years. It is because of concerted efforts of researchers from multidisciplinary fields, sol-gel science transformed to technology. Several products are already commercially available for applications in optical coatings, nanocomposites, and public healthcare. Potential applications in the areas of biosensors and environmental monitoring are expected. Newer applications with nanotechnology appear too exciting. An attempt has been made to address important applications of sol-gel technology, particularly in sensing techniques from the defence perspective.Keywords: Sol-gel technology, nanomaterials, healthcare, sensors, defence applications Revised 19 November 2006 . INTRODUCTIONThe term sol-gel was first coined in the late 1800s. It generally refers to a low-temperature method using inorganic precursors that can produce ceramics and glasses with better purity and homogeneity than through high temperature conventional processes 1 . Two most attractive features of the sol-gel process are that it can produce compositions that cannot be created with conventional methods, and that the mixing level of the solution is retained in the final product, often up to the molecular scale.Sol-gel method has been successfully used to manufacture a variety of products, viz., bulk glasses 2 , optical fibers 3 , special coatings, ultra-pure powders, and multifunctional materials. Figure 1 shows different types of materials made from sol-gels. Sol-gelprocessed transparent porous matrix offers the possibility of doping various organic and inorganic molecules [5][6][7][8] . Sol-gel process has been used to Defence Science Journal, Vol. 57, No. 3, May 2007, pp. 241-253 © 2007 241 REVIEW PAPERfabricate materials which can be used as new laser materials, nanocomposites, biomimetic systems, and so on. Because of potential in fabrication of a wide variety of new materials, understanding of sol-gel processes has become the centre of interdisciplinery research, viz., physics, chemistry, biology, biotechnology, biochemistry, electronics, and related engineering branches. Sol-gel materials have a wide range of applications, from environmental monitoring, biosensors for healthcare, to nanotechnology for sensing clinically-important analytes. . BASICS OF SOL-GEL PROCESSThe sol-gel process is a versatile technique which involves the transition of a predefined composition from liquid sol (mostly colloidal) phase into a solid gel phase 9 . Sol-gel processing involves the hydrolysis of a metal alkoxide followed by condensation and polymerisation reactions, leading to the sol-gel state.242 DEF SCI J, VOL. 57, NO. 3, MAY 2007 These general reactions are shown below:Metal alkoxides are most popular because these react readily with water. The most widely used metal alkoxides are the alkoxysilanes, such as tetramethoxysilane (TMOS) a...

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Section: Sol-gel Glasses Optical Fibres and Nanocomposite Materialsmentioning

confidence: 99%

“…Fibres up to 1 m length were drawn 35 . These fibres were studied for pH sensing and as laser dye when appropriately doped by fluorescent molecules, viz., fluorescein and rhodamine-6G 36,37 . Nanoparticles of semiconductors or metals have been widely investigated for applications in nonlinear optics 38 .…”

Section: Sol-gel Glasses Optical Fibres and Nanocomposite Materialsmentioning

confidence: 99%

Sol-gel Technology for Sensor Applications

Chaudhury

Gupta

Gulia

2007

DSJ

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“…They are considered as a good candidate for nanotechnology applications due to their unique properties of high surface-to-volume ratio (Shen et al 2009;Yun et al 2003;Themistos et al 2009). In photonics, nanowires are used as optical waveguides, and particularly silicon-on-insulator (SOI) based nanowires have been used as optical sensors because they have the advantage of high index contrast and low optical power losses (Dell'Olio and Passaro 2007; Sirbuly et al 2006;MacCraith et al 1991;Lou et al 2005;Wang and Dai 2010).…”

Section: Introductionmentioning

confidence: 99%

Surface plasmon resonance-enhanced light interaction in an integrated ormocomp nanowire

et al. 2016

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An integrated ormocomp nanowire coated with gold metal layer is proposed and its optical characteristics with the effect of surface plasmon resonance (SPR) are studied. The integrated rib-like nanowire has a trapezoidal shape with sidewall angles of 75°. It is coated with 50 nm gold layer to introduce the SPR and enhance the evanescent field in the sensing region located at the dielectric/metal interface. The possible field modes, the normalized power confinement, and the SPR peak position of the nanowire are studied over the wavelength and the metal thickness by using the full-vectorial H-field FEM in quasi-TM mode. The attenuation coefficient of the nanowire, the SPR peak wavelength, and the wavelength shift is experimentally extracted for three different cladding materials. The redshift of the supermode coupling between the dielectric mode and the anti-symmetric supermode is observed with the higher cladding-index and larger metal thickness. The improvement of the power confinement in the sensing region with the SPR effect is ten times (109) better than a previous similar study.

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“…In fact, there are a wide variety of dye molecules and novel sensors, which are being investigated and developed on the basis of the sol-gel method (11)(12)(13)(14)(15)(16). One benefit of this procedure is related with the fact that the method involves low temperature process from liquid phase, which prevents the pyrolysis of organic molecules.…”

Section: Introductionmentioning

confidence: 99%

Dependencia espectral de la eritrosina B con el pH en soluciones tampón y en recubrimientos sol-gel de silice

Montero¹,

García²,

Broncano³

et al. 2008

Bol. Soc. Esp. Ceram. Vidr.

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Thin coatings optically sensitive against pH are obtained by entrapping erythrosin B molecules in a sol-gel silica matrix. Comparisons between optical spectra of erythrosin B in solutions and those once entrapped in silica coatings are performed for pH ranging from 0.5 to 12.0. Significant differences between both kinds of spectra (solutions and coatings) of erythrosin B are observed. Main changes are displayed in the absorption spectra for neutral to basic pH. Furthermore, the erythrosin B doped coatings show memory effect or hysteresis in their spectral response against pH. This means that absorption spectra depend on the direction of the pH change. Likewise, the photoluminescent spectra of erythrosin B in buffered solutions exhibit pH dependence and a maximized response in the basic pH range. On contrast, no significant photoluminescence from the erythrosin B entrapped in the silica coatings is observed. Results are mainly discussed on the basis of different optical response of polyprotic forms of erythrosin B and possible interactions between the molecule and oxygen as well as the porous walls of the sol-gel silica matrix. In addition, the presence of diffusional barriers, which hamper the flowing of protons and other associated ions, is taken into account. Good agreement with previous observations about low absorption of polyprotic cationic and neutral forms of erythrosin B is found. Keywords: A. Optical materials, B. Glassy coatings, C. Sol-gel chemistry, D. Optical properties, D. LuminescenceDependencia espectral de la eritrosina B con el pH en soluciones tampón y en recubrimientos sol-gel de silice.Se han obtenido recubrimientos delgados ópticamente sensibles al pH mediante atrapamiento de moléculas de eritrosina B en matrices de sílice obtenidas por sol-gel. Se compara la respuesta espectral de la eritrosina B en solución y atrapada en los recubrimientos de sílice para un intervalo de pH comprendido entre 0,5 y 12. Se observan apreciables diferencias entre ambos tipos de espectros (en solución y en recubrimiento) de la eritrosina B. Los principales cambios aparecen en los espectros de absorción para el intervalo neutro y básico de pH. Además, los recubrimientos dopados con eritrosina B muestran respuestas espectrales frente al pH con efecto de memoria o histéresis. Esto significa, que el espectro de absorción depende del sentido del cambio del pH. De forma análoga se ha visto que los espectros de fotoluminiscencia para la eritrosina B en soluciones tampón dependen del pH, mostrando su máxima respuesta en el intervalo básico de pH. Por el contrario, para la eritrosina B atrapada en los recubrimientos de sílice no se observa señal de fotoluminiscencia. Se discuten los resultados teniendo en cuenta principalmente, la diferente respuesta óptica de las formas polipróticas de la eritrosina B y sus posibles interacciones con el oxígeno así como con las paredes de los poros de la matriz sol-gel. Además, se considera la presencia de barreras difusionales hacia la molécula que impiden el flujo de protones y otros...

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Optical waveguide sensor using evanescent wave excitation of fluorescent dye in sol-gel glass

Cited by 128 publications

References 3 publications

Sol-gel Technology for Sensor Applications

Sol-gel Technology for Sensor Applications

Surface plasmon resonance-enhanced light interaction in an integrated ormocomp nanowire

Dependencia espectral de la eritrosina B con el pH en soluciones tampón y en recubrimientos sol-gel de silice

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