An International Research Journal

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SSN : 0971 - 3093

Vol  12, Nos 2&3, April - September, 2003

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Asian Journal of Physics

Vol 12,  Nos  2&3 (2003) 183-354



Novel signal processing for advanced optical sensors

M N Taib and R Narayanaswamy                                                                                                                                                        183

Long period grating sensors to monitor fuel quality

R Falate, JL Fabris, M Muller


Effects of temperature on glued fiber Bragg grating sensors,

Riccardo Falciai and Cosimo Trono                                                                                                                                                     213


Ruthenium-based optical fiber sensor for gaseous oxygen detection

Gaetano Di Marco, Maurizio Lanza, Giuseppe Calogero. Patrizia Bizzarri and Anna Grazia Mignani                                              219


Trace detection of nitriles in water using long period gratings in multimode optical fiber                                        

P Suresh Kumar, Diesh Kumar, R S Thomas Lee, CPG Vallabhan,   VPN Nampoori and  P Radhakrishnan                                      233


Fiber optic chemical sensor for air pollutant measurement: design, development and applications

Ang Soo Seng, M S John and Anand Asundi                                                                                                                                        237


H2S sensing properties of H2SO4 treated Sn02:Pd thin films in temperature cycling mode.

S C Gadkari, V R Katti, Manmeet Kaur, K P Muthe, A K Debnath, A K Dua,S K Gupta and V C Sahni                                             303

Comparative studies of surface modified SnO2 as pellet and thin film for LPG sensing.

Niranian S Ramgir and Initiaz S Mulla                                                                                                                                                  311

Porous silicon: a natural nano structure for vapour sensing applications.

H Saha, J Das, S M Hossain                                                                                                                                                                   323

Au-polyaniline nanocomposite: sensor for methanol vapours.

Anjali A Athawali, S V Bhagawat and Prachi P Katre                                                                                                                           331

Electrical conductivity, humidity sensing properties of SnW04-SnO2 composites synthesized by in situ method.

R Sundaram, O M Sreedharan, C Mallika and K S Nagaraja                                                                                                                339

TCNQ-functionalized ormosil based electrochemical biosensors.

P C Pandey, S Upadhyay, N K Shukla and S Sharma                                                                                                                             345




The field of optical and solid state sensors has emerged during the past twenty years as an important part of modern instrumentation and control systems. The continuous progress of the optoelectronic and microelectronic technologies together with developments in material science has sustained the sensor area growth for many years. Contributing to sensor progress are advances in chemistry, biology, surface science, chaos and information theory, signal processing, nanotechnology, and simulation tools. All of these aspects, which are stronglypluridiscip linary in character, together with promising markets on the horizon in the fields of medicine, industrial processes, transportation, space, and food and beverage control, are contributing to the birth of the sensor science discipline. The sensors have been developed into commercial products, and new sensing and transduction methods have been developed that will lead to new products and system approaches. The global market for sensors is expected to reach more than $50 billion by 2008. Much innovation in sensor technology has occurred in recent years. The related material is spread among various publications, hiding the big picture. The purpose of this special issue is to put together a set of original research papers that represent the best in optical and solid state sensors area, showing the State of Art as well as breadth and depth of current research. I am grateful to authors for responding to my call for papers and for their help in returning the revised papers fairly rapidly. My sincere thanks are due to the publisher of Asian Journal of  Physics and the Chief  Editor, Professor V.K. Rastogi, for appointing me the Guest  Editor of  this special issue.


B D Gupta

Guest Editor

Physics  Department, Indian Institute of  Technology Delhi, Hauz Khas, New Delhi-110 016, India;

Asian Journal of Physics                                                                                                  Vol. 12, Nos 2&3 (2003) 183-204

Novel signal processing for advanced optical sensors

M N Taib1 and R Narayanaswamy2

1Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM)

40450 Shah Alam, Selangor D E Malaysia

2 Department of Instrumentation, and Analytical Science,UMIST, P O Box 88

Manchester M60 1QD, U K


A novel technique for processing signals of an optical fibre sensor has been demonstrated  in this paper. A multilayer artificial neural network (ANN), with only one hidden layer, was trained via the recursive prediction error (PRE) algorithm to adapt to the input-output signals from a Light Emitting Diode  used in conjunction with a reflectance fibre optic sensor. Three LEDs (red, Orange and yellow) operating in the visible region at peak wavelengths of 660nm, 620nm and 590nm,respectively were employed as light source, the optical signals reflected  from the tip of a fibre optic sensor based on immobilized thymol blue were correlated directly to pH measurements. A network architecture of 3-input neuros, 13-hidden neurons and 1-output neuron was found most suitable for this application and a linear calibration output  was produced for a pH measurement range of 0.90 to 10.28.The application of (ANN) to the optical fibre sensor also exhibited a very robust system where fluctuations in the sensor signals of upto 7.0% can be tolerated before the prediction error magnitude becomes larger than 1.0pH.

Total Refs: 23


Asian Journal of Physics                                                                                                  Vol. 12, Nos 2&3 (2003) 205-211


Long Period Grating Sensor to monitor Fuel Quality


Rosane Falate, José Luís Fabris, Márcia Müller and Hypolito José Kalinowski

Centro Federal de Educação Tecnológica do Paraná

Av. Sete de Setembro, 3165 – 80230-901 Curitiba, Brazil


We describe the production and characterisation of  Long Period Gratings in fibre optics. The gratings are written in standard single-mode fibre using the electrical arc technique while their transmission spectrum is used to control the grating length. Optical characterisation  and  wavelength dependence  with temperature  and  refractive  index of the external medium are  shown. An  application of  the LPG as a  sensor to monitor the fuel quality (Brazilian standard mixture of ethanol and gasoline) is presented.

Total refs: 16

Cited: 7 times


Asian Journal of Physics                                                                                                          Vol 12, Nos 2&3 (2003) 251-256


An evanescent-wavelength optical fiber relative humidity sensor

Sunil K Khijwania, Rajeev Jindal and Jagdish P Singh

Diagnostic Instrumentation and Analysis Laboratory


A novel optical fiber relative humidity sensor is proposed using a single U-bend plastic clad silica fiber. The sensor is fabricated using a thin film of PVA/CoCl2 coated on the bare fiber core. A comprehensive study of the sensor was made in terms of performance optimization and practical uses. Sensor, comprising  of  fiber with a smaller core diameter is found to be more sensitive. The sensor exhibits a short response time, high repeatability and reversibility. ©Anita Publications. All rights reserved.

Total Refs: 7

1. Hesse H C, East German Patent, 106(1974)86.

2. Russell A P, Fletcher K S, Anal Chim Acta, 170(1985)209


Asian Journal of Physics                                                                                                 Vol 12, Nos 2&3 (2003)

Fiber-optic proximity sensor for mechatronic applications

Manish Ahuja, Amit Sadhu, M R Shenoy and S K Saha1

Department of Mechanical Engineering, Indian Institute of Technology Delhi

1Department of Physics, Indian Institute of Technology Delhi

Hauz Khas, New Delhi-110 016, India (  M R Shenoy)


This paper describes the development of a fiber optic based proximity sensor to control the motion of objects moving on the conveyor belt of an assembly line. The sensor can detect the presence and absence of the object, with certain surface qualities, in the sensing zone and give a digital output.

Total Refs: 4


Asian Journal of Physics                                                                                                        Vol 12, Nos 2&3 (2003)


In-Fiber Gratings: Evolution, Optics and Applications in Sensing

Bishnu P Pal

Departmen of Physics

Indian Institute  of Technology Delhi, Hauz Khas, New Deli-110  016, India


Cited by Optical fiber sensors: A versatile technology platform for sensing

BP Pal - Journal of the Indian Institute of Science, 2014 -


Optical fibers are now taken for granted as signal transmission media for telecommunication and the Internet. Optical fibers also provide a versatile platform for sensing a host of physical and chemical effects, and parameters of interest. Though optical

Cited by 3 Related articles All 4 versions

3. Optical Waveguide Sensors

BP Pal - Handbook of Optical Sensors, 2014 -

Optical waveguide, by definition, is a central region called the core of certain refractive index, which is surrounded by either one medium of lower refractive index or two optical media, each of which has refractive index lower than that of the core.


Asian Journal of Physics                                                                                         Vol 12, Nos 2&3 (2003)

Non-invasive, quantitative estimation of tissue physiological parameters with diffuse optical tomography (DOT)


Gargi Vishnoi

Biomedical Engineering Group, BJM Schoool of Biosciences and Bioengineering

Indian Institutue of Technology Bombay,powai, Mumbai-400 076, India

Diffusing photons can be used as sensing mechanism to probe and characterize optically thick turbid medium such as human tissue. Here, Diffus Optical Tomography (DOT)


Asian Journal of Physics                                                                                                         Vol 12, Nos 2&3 (2003)

Optical sensor system for non-invasive medical diagnostics


M Mukunda Rao, R Arul Ram and G V Srikrishnan

Biomedical Sciences Division

Sri Ramachandra Medical College & Research Institute (DU)

1,Ramachandra Nagar, Porur, Chennai-600 116, India


Asian Journal of Physics                                                                                                        Vol 12, Nos 2&3 (2003)

Humidity sensing characteristics of potassium doped barium strontium titanate

(Bax Sr1-x TiO3) thin films prepared by sol-gel technique

Somnath C Roy, Uppireddi Kishore, G L Sharma and M C Bhatnagar

Thin Film Laboratory, Department of Physics

Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110 016, India


Asian Journal of Physics                                                                                                        Vol 12, Nos 2&3 (2003)

Electrical characterization of (Ba,Sr)TiO3  thin films grown by sol-gel technique for humidity sensor applications

Seema Agarwal, M C Bhatnagar,and G L Sharma

Thin Film Laboratory, Department of Physics

Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110 016, India

(Ba,Sr)TiO3 (BST) thin films made by sol-gel technique are polycrystalline and porous in nature. 


Asian Journal of Physics                                                                                                            Vol 12, No 2& 3 (2003)  339-344

Electrical conductivity, humidity sensing properties of SnWO4 – SnO2 composites synthesized by in situ method

R Sundaram, O M Sreedharan, C Mallikaa and K. S. Nagaraja*

*Department  of Chemistry, Loyola  Institute of   frontier energy (LIFE ),  Loyola  College, Chennai -34,India

aThermodynamics and Kinetic Division, IGCAR, Kalpakkam, India

Phone: +91-44-28175660  Fax: +91-44-2817.5SM


An intimate mixture of SnO and WO3 in the mole ratio 4:1 was prepared by the high temperature route. as well as with 2mole % of LiOH. H2O and Mg(OH)2.H2O was sintered at 973K in air atmosphere in the form of cylindrical discs. The XRD of this sintered sample indicates the formation of SnWO4 and SnO2 phases only. DC. electrical  conductivity measurements over the temperature range 310-510 K in air atmosphere form which the activation  energies  were determined. The current was found to increase  linearly with the applied field indicating the Ohmic nature. The current increases exponentially against the temperature indicating the semiconductive nature of the sample. The activation energy for D.C. conductance was found to be 0.69 eV, The material was subjected to humidity sensin::, using d.c resistance measurements as a function of relative humidity in the range of 5-981X, RII, achieved by different water buffers thermostated at 298K. A plot of log R vs Relative humidity (RH) was made to compare the humidity sensing characteristics of the material. The sample was doped with 2mole % of Li* and Mg' to enhance the sensitivity towards moisture. It could he inferred that the drop in D.C. resistance for the Lit doped material is quite high when compared to that of undoped and Me* doped specimens. The sensitivity factor, S, (Rs.A/RomiA) for SWSO.1S, and Me doped samples are found to be 104, 21053 and 20, respectively. It is evident that the in situ generated composite of SnW04-SnO2 shows higher sensitivity (21053) than the same non-in situ generated composite sensitivity (6364 The response and recovery characteristics of this compound were assessed. 0 Anita Publications. All rights reserved

Total Refs : 12

1 Introduction

The measurement and control of humidity is important in many areas including meteorology, medicine, food production, agriculture and domestic environment. The measurement of relative humidity' seems to be very convenient. Of the various materials utilized for humidity detection, the metal oxides, which are physically and chemically stable, have been widely investigated at both elevated and room iemperatures24. Investigations on materials based on electrolytic manganese oxide have proved to be highly promising and being operative at room temperature". However, our earlier investigations indicate that materials that possess metastable coexistence can have excellent sensitivity towards moisture". The main problem in handling tin oxides based humidity sensors is their thermal stability as their stoichiometry varies with sintering temperature though they are capable of operating in the D.C. mode unlike the conventional ceramic materials which require an A.C. mode. Hence, the present investigation aims at the development of humidity sensors operating in the D.C. mode based on tin oxide - tin tungstate composites obtained by in situ method.

2 Experimental

2. I Preparation of SnW04-SnO2compo.sites

Since the mechanical mixtures of SnW04-SnO2 composites showed high sensitivity towards moisture, a novel in situ method of synthesizing these composite was resorted for further improvement in the sensitivity. This type of in situ generation provides grain boundaries and hence enhances better efficiency. Intimate mixtures of undoped and Li` or Mg,21. (2 mole %) doped SnO2 and W01 in 4:1 mole

Asian Journal of Physics                                                                                          Vol 12, Nos 2&3 (2003) 345-354.

TCNQ- functionalized ormosil based electrochemical biosensors

P C Pandey, S Upadhyay, N K Shukla and S Sharma

Department of Chemistry, Banaras Hindu University, Varanasi-221 005;, (P C Pandey)


The electrochemical biosensors based on tetracyanoquinodimethane (TCNQ) encapsulated within palladium-linked organically modified sol-gel glass (ORMOSIL) and redox enzyme modified graphite paste electrodes are reported. The new ormosil is made using Pd_linked silane precursor containing, trimethoxysilane, HCl and TCQN powder at 25 ˚C.  Two electrochemical biosensors, the first one for glucose and second one for peroxide are reported using TCNQ-functionalised ormosil and redox enzyme glucose oxidase/Horseradish peroxidase (HRP)] incorporated within graphite paste electrode. The performance of glucose biosensor and peroxide biosensor is examined based on cyclic voltammetry and amperometric measurements. The sensing of glucose is based on the measurement of anodic current at 0.25 vs Ag/AgCl as a function electrocatalytic oxidation of glucose oxidase on TCNQ-functionalized ormosil-modified electrode whereas the same for peroxide involves the measurement of cathodic current at 0 mV vs Ag/AgCl as a function of electrocatalytic reduction of Horseradish peroxidase on similar modified electrode system. Anodic oxidation of peroxidase has also been examined using four types of graphite paste modified electrodes. The Electrode-1 is made in absence of functionalized ormosil and HRP, Electrode-2 is made in the presence of HRP only, Electrode-3 is made in the presence of HRP and functionalized ormosil whereas Electrode-4 is made in the presence of functionalized ormosil only.The results suggest that peroxide undergoes both direct and electrocatalytic oxidation at anodic potential on functionalized ormosil-modified electrode.© Anita Publications. All rights reserved.

Total Refs:14


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