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Gold-nanoparticle-based fiber optic sensor for sensing the refractive index of environmental solutions
(2018-08-01)
Houngkamhang, Nongluck
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Charoensuwan, Sittan
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Sonthipakdee, Onanong
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Nawattanapaiboon, Kawin
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Somboonkaew, Armote
Here an optical fiber modified with gold nanoparticles was successfully fabricated to sense the refractive index of a chemical solution surrounding its surface, with the potential of utilizing this sensor as a biosensing device. Gold nanoparticles, with an average diameter ~20 nm, were synthesized via the citrate reduction method and used to functionalize the glass core of an optical fiber. The sensing principle, which is based on localized surface plasmon resonance, requires the metal gold nanoparticles to be exposed to both the incident and absorbing lights, with the potential detection capabilities determined from the observed light intensity measurement. The optical fiber was uncladded at its center to expose the glass core fiber, and gold nanoparticles were immobilized on the exposed surface using a silane coupling agent. The sensitivity of the gold-nanoparticle-modified optical fibers in measuring the refractive index changes of a solution was compared for unclad lengths ranging between 1 and 2 cm. The attenuation of light depended on both the refractive index of solution and the length of the unclad fiber. The results showed that the fiber sensitivity increased as the unclad length increased due to greater amount of gold on the surface. Antibody-A, which has a specific binding to antigen-A, was then covalently linked to the fiber surface via an amide bond to demonstrate the potential bio-sensing platform of this sensor. The antibody-A functionalized optical fiber was used to detect the red blood cell samples in groups A, B, and O, where it effectively detected both the specific and non-specific binding signals. This fiber optic biosensor therefore provides a low-cost and simple fabrication setup that has potential field applications. Moreover, this setup could potentially be applied to detect other types of whole cell samples.
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Multi wgm light probes generated by distributed panda resonator system
(2016-06-01)
Sappajak, S.
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Patharacorn, P.
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Chaingga, S.
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Yupapin, P. P.
Multi-micro-sensing probes are generated by whispering gallery mode (WGM) of light within a PANDA ring resonator, from which the sensing device model is designed and simulated using the commercial MATLAB and Opti-wave programs. The WGMs are generated by travelling light signals within the nonlinear micro-ring resonator. The specific control of the concerned device parameters is provided, from which the generated WGM probes are obtained and used to form the distributed sensing head, where the exchange between the measurement environments and sensing device parameters can be interpreted to form the required signals. In practice, the output signal can be obtained by using the detected output device (i.e., photodetector) via the add port output signals, where the measurements in terms of phase or wavelength changes can be interpreted relatively to the applied physical content parameters. Results obtained have shown that the linear relationship between angular velocity and the change in wavelength can be achieved, which is useful for sensing device application. In general, the large volume or contents can be employed by using the distributed sensor configuration.
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Temperature effect on refractometric double ring resonator
(2015-01-01)
Mohamad, Azam
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Aziz, M. S.
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Bahadoran, Mahdi
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Chaudary, Kashif
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Arif Jalil, M.
The effect of temperature on double ring resonator (DRR) glucose sensing is investigate theoretically and proposed. Different from other optical resonator, the pulse laser is used as an input source and the vertical DRR configuration is used. The concept for pulse propagation is based on the split-step Fourier method. Result shows that the detection of glucose is measured by optical losses and the losses at 26°C are 1.86 dB at through and 0.93 dB at drop port, respectively. The performance of glucose sensing on DRR is degraded by temperature. Effect of temperature creates more losses which results total loss of 2.01 dB at through and 1 dB at drop port when temperature increase by 1°C.
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Effect temperature in chemical sensing using triple stage microring resonator
(2015-01-01)
Mohamad, Azam
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Bahadoran, Mahdi
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Aziz, Safwan
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Chaudary, Kashif
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Jalil, Muhammad Arif
The split-step Fourier technique is used to study the effect of temperature in triple stage microring resonating sensor (TSMRRS). The optical bright soliton beam is used as the probe pulse into the TSMRRS and the effect of temperature variations on various concentrations of glucose in deionize water is investigated. The detection of glucose is measured by intensity variations of output signals from through and drop ports of TSMRRS. The temperature variations cause an exact intensity reduction of glucose concentration in deionize water when the temperature increased by 1 °C. The performance of TSMRRS glucose sensor is improved for temperature range similar with standard room temperature which shows that TSMRRS is suitable candidate for chemical sensing application.
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Photocurrent enhancement between two coplanar schottky-barriers on silicon MSM photodetector
(2013-06-03)
Atiwongsangthong, Narin
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Niemcharoen, Surasak
Gain properties of dc and ac photocurrent generated between two Schottky barriers coplanarly placed on silicon metal-semiconductor-metal photodetector have been investigated experimentally. The test structure has two square Mo/n-Si Schottky barrier junctions on an n-type silicon substrate with a resistivity of 9-12 Ω-cm and the junction internal separation is 20μm. The current-voltage (I-V) characteristics under illumination in visible range showed a rapid increase in the photocurrent at higher bias region. From the I-V characteristics and noise measurements, increase in photocurrent was ascribed to avalanche multiplication of carriers photogenerated in the reverse-biased Schottky junction. From observation of optical signal demodulation at low frequencies (10 kHz and 50 kHz), it was found that multiplication factor larger than 100 at 10 kHz and 30 at 50 kHz was achieved respectively. © (2013) Trans Tech Publications, Switzerland.
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Multifunction sensors using coincidence dark-bright soliton pair in a MZI
(2012-04-20)
Mitatha, Somsak
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Piyatamrong, Bunjong
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Tamee, Kreangsak
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Yupapin, Preecha P.
A new system of multifunction sensors using dark and bright solitons in a Mach-Zehnder interferometer (MZI) is proposed. In this concept, the coincidence dark and bright soliton pair within the MZI can be arranged by using the phase controller, in which (|D〉) and (|B〉) states represent the orthogonal dark and bright solitons, respectively. We assume that both solitons are input into the MZI ports simultaneously (coincidently). The randomly input dark and bright soliton states into the MZI ports can perform the change in phase after propagating through a phase shifter/sensing unit, in which the phase change recovery using the phase related measurement device can be provided. By using the orthogonal soliton behaviors, a sensing application using a soliton(photon) pair can be formed. Moreover, the soliton power can be reduced to a single photon power (10 -6 W), where finally the single photon sensor can be operated. The self calibration concept between signal and referencing arms of a MZI can also be established, which is discussed in details. © 2001-2012 IEEE.
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Force sensing device design using a modified add-drop filter
(2012-01-01)
Kulrod, K.
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Sirawattananon, C.
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Mitatha, S.
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Srinuanjan, K.
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Yupapin, P. P.
We propose a new sensing device using a modified add-drop filter known as a PANDA ring resonator type, in which the sensing unit is consisted of an optical add/drop filter and two nanoring resonators, where one ring is placed as a sensing device, the other ring is set as a reference. In operation, the external force is assumed to exert on the sensing ring resonator, which can form the measurement. The finite difference time domain (FDTD) method called Optiwave is used to manipulate the sensing behaviors of the proposed system. The obtained results have shown that the change in wavelength due to the change in sensing ring radii is seen, in which the wavelength shift of 1 nm resolution is achieved. The recovery and the reciprocal signals can also be formed, which can be used to approach to many advantages of measurements, including the possibility of standardizing measurement accuracy. The behavior of light within a PANDA ring resonator is also analyzed and reviewed. © 2010 Published by Elsevier Ltd.
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An artificial nose based on M-porphyrin (M = Mg, Zn) thin film and optical spectroscopy
(2011-12-01)
Kladsomboon, Sumana
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Pratontep, Sirapat
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Puntheeranurak, Theeraporn
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Kerdcharoen, Teerakiat
Artificial nose has recently become an emerging instrument for quality assurance in the food industry. These paper present the optical gas sensors based on Magnesium-5,10,15,20-tetra phenyl-porphyrin (MgTPP) and Zinc-5,10,15,20-tetra phenyl-porphyrin (ZnTPP) thin films and their application as an artificial nose. Based on the measurement of optical absorbance response using a general UV-Vis spectroscopy, this artificial nose was tested to discriminate various volatile organic compounds (VOCs) and Thai beverages. Atomic force microscopy (AFM) and X-rays diffraction (XRD) were used to confirm the polycrystalline structure of the sensing materials. Density functional theory (DFT) calculations reveal that MgTPP interacts more strongly with the VOCs than ZnTPP, especially with methanol. The classification results of VOCs and Thai beverage vapors using the principal component analysis indicate that both MgTPP and ZnTPP-based artificial noses can be an efficient tool for quality assurance of alcoholic beverages. Copyright © 2011 American Scientific Publishers All rights reserved.
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White noise in silicon-based planar metal-semiconductor-metal photodiodes
(2008-10-06)
Khunkhao, S.
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Nanthivatana, P.
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Niemcharoen, S.
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Titiroongruang, W.
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Sato, K.
Low-frequency 3-100 kHz shot noise (white noise) emerging from photoinduced current in Mo/n-Si/Mo structures leaving undepleted region has been observed under different bias and optical intensity conditions. The measurements revealed that the current noise observed depends not only on the illumination intensity levels but also on bias voltage. The current noise observed is expressed as S(ω)=2IΓ2 and analyzed, where I and Γ2 is the average current and noise factor, respectively. The measurements reveal that Γ2 has strong bias dependence, lying Γ2- 0.01 to about unity corresponding to simple shot noise. Such experimental results are explained, stating that the reduction of cross correlation between drift and diffusion currents and autocorrelation of drift current component determining the level of noise occurs with decrease in SCR width bias-dependent. To explain the behavior of observed noise more properly, we propose, in addition to the mechanisms above, that the reduction in autocorrelation effect of each current component plays an important role to decrease the relevant noise to such extremely low levels. © 2008 IEEE.
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On laterally spreading of space-charge-region in planar metal-semiconductor-metal structures
(2003-10-01)
Khunkhao, S.
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Yasumura, Y.
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Kitagawa, K.
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Masui, T.
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Sato, K.
Lateral spreading along the surface of space-charge-region (SCR) of planar metal-semiconductor-metal (MSM) structures has been investigated. Planar MSM structures have been attracted much attention as viable optical sensor structures. For this purpose, the SCR of such a structure plays a key role in generating photocurrent and thus, in dc (static) and/or low frequency scheme, the wider SCR along the active surface is the better from the efficiency point of view. To study the spreading properties of the SCR along the surface of MSM structures, we prepared planar MSM structures leaving the undepleted region between the electrodes. We examined their SCR spreading through the photocurrent-bias voltage characteristics. The experimental results were compared with the numerical simulation using a quasi-1D (one-dimensional) model of such a planar structure. It was found that the change in the photocurrents is proportional to the square root of the bias applied, implying that the current varies with the lateral spreading of the SCR. Further, the value of the surface spreading of the SCR might be roughly equal to the results predicted from the numerical simulation. These results also suggest that the effective photocurrent generation is occurring principally at the very surface of the SCR. © 2003 Elsevier Ltd. All rights reserved.

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