Capacitive Transduction for Liquid Crystal Based Sensors, Part II: Partially Disordered System

Abu-Abed, Alaeddin S.; Lindquist, Robert G.

doi:10.1109/jsen.2008.925451

Cited by 11 publications

(6 citation statements)

References 25 publications

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“…Such mechanism of capacitance steering was also analyzed [1][2][3] even with periodic electrodes [4]. Similar setup can be potentially used for chemical and biological sensors [5]. The NLCs not only interact with the electric field, but also with the magnetic field, which was also used for capacitance steering [6,7].…”

Section: Introductionmentioning

confidence: 97%

Optical steering of mutual capacitance in a nematic liquid crystal cell

Sala

Sala-Tefelska

2017

J. Opt. Soc. Am. B

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In this study a variable capacitor made of Nematic Liquid Crystal cell is proposed and analyzed theoretically. The mutual capacitance is steered with an optical beam of a Gaussian shape launched into the cell. The optical field changes the orientation of the molecules and affects the capacitance. By using Frank-Oseen elastic theory the molecular reorientation is simulated. The influence of various parameters on capacitance such beam width, anchoring condition, externally applied voltage, beam power and launching position is presented. For instance, the maximum tuning range is achieved for wide beams and the molecules initially aligned close to the propagation axis. It is also proved that launching position, especially for narrow beams, has limited influence on capacitance. The proposed component can be used, for instance, in optical power meters, as a feedback in laser or diode systems or just as a variable capacitor in optoelectronic circuits. One of the advantages of this device is that the beam passes through the element, so steering of the capacitance or measuring the parameters of the beam can be realized without splitting the beam. Moreover, due to the low thickness of the liquid crystal layer the attenuation is very low.

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Section: Introductionmentioning

confidence: 97%

Optical steering of mutual capacitance in a nematic liquid crystal cell

Sala

Sala-Tefelska

2017

J. Opt. Soc. Am. B

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“…[1][2][3] In these sensors, the molecular alignment in the LC film is altered in response to some environmental conditions or external stimuli. For most chemical and biological sensors, the orientational behavior of liquid crystals near surfaces is exploited.…”

Section: Introductionmentioning

confidence: 99%

“…In a previous effort, the authors have demonstrated a capacitive technique in monitoring the LC deformations. 3 In these sensors, when the director axis orientation alters, the electrical properties of the LC change and the capacitance will change accordingly. The capacitive method has also proven the capability of tracking the LC director and degree of ordering.…”

Section: Introductionmentioning

confidence: 99%

Coupled surface plasmon resonance sensor with sensitive liquid crystal layer

et al. 2011

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This paper presents an optical sensor based on the surface plasmon resonance (SPR) phenomenon, involved with liquid crystal (LC) sensitive layer. This sensor has potential applications in chemical and biological systems. We present a tracking method for the state of alignment and degree of ordering of the partially ordered LC film. This can be achieved via the SPR propagation constant and the critical angle at the interface between a metal and an LC film. The proposed idea is also investigated experimentally. For this purpose, we fabricated gold nano-dots array on an optical fiber tip for localized SPR sensing. The spectral position of the maximum loss in the transmission spectra depends on the refractive index of the medium surrounding the sensor fiber tips. This allows for tracking the LC profile parameters.

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“…To verify these transitions of NLCs, we have the optical observation, which is observed visual inspection or optical microscopy as well as the electrical observation, which is measured the capacitance provided by ability to identify and track the average transition. [4][5][6] This sensor structure by the gold micro-electroplating technique is quite useful to steadily support a 10μm thickness of NLCs.…”

Section: Introductionmentioning

confidence: 99%

Sensing Characteristics of Chemical Agents by Using Liquid Crystal-Based Chemical and Biological Sensors

Namkung

Zou

et al. 2010

Conference on Lasers and Electro-Optics 2010

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This paper reports the design of a microstructure comprising an interdigitated capacitance structure for the detection of vapor-phase analytes based on nematic liquid crystal (NLC) sensor. The NLC sensor is tested by using demethyl-methylphosphonate (DMMP) detection to change the orientational response of the liquid crystal molecules and demonstrated by the optical monitoring as well as the capacitive monitoring. Finally, vapor-phase analyte concentrations down to the parts-per-billion (ppb) level have been tested.

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Capacitive Transduction for Liquid Crystal Based Sensors, Part II: Partially Disordered System

Cited by 11 publications

References 25 publications

Optical steering of mutual capacitance in a nematic liquid crystal cell

Optical steering of mutual capacitance in a nematic liquid crystal cell

Coupled surface plasmon resonance sensor with sensitive liquid crystal layer

Sensing Characteristics of Chemical Agents by Using Liquid Crystal-Based Chemical and Biological Sensors

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