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Calculation of the bandwidth of a graded-index optical fiber using experimentally measured quantities
(© 2007 Dhaka University Journal of Science, 2007-01) Alam, Shaif-ul; Abedin, Kazi Monowar; Haider, A F M Yusuf; Department of Mathematics and Natural Sciences
Construction and operation of a dispersive laser raman spectrograph using interference filter
(© 2008 Journal of Bangladesh Academy of Sciences, 2008) Abedin, KM; Farhad, SFU; Islam, MR; Talukder, Aminul I; Haider, A F M Yusuf; Department of Mathematics and Natural Sciences
A dispersive laser Raman system was designed and constructed using a helium-neon (He-Ne) laser as an excitation source, and an interference filter in the reflection mode for Raleigh filtering instead of the more common holographic notch filter. A commercially available spectrograph equipped with a cooled CCD camera was used to acquire the Raman spectra. The constructed laser Raman spectrograph was found to have excellent performance and sensitivity. Stokes Raman spectra of some common chemicals were acquired by the system, and the wavelengths of spectral lines agreed well with the literature values, within experimental error. The useful spectral range of the system is about 200-4000 cm-1. It was also possible to acquire anti-Stokes Raman spectra of one chemical (CCl4) without much difficulty. We hope to use the system for chemical identification of molecules as well as quantitative chemical analysis. To our knowledge, this is the first laser Raman system constructed in Bangladesh.
Construction of laser raman system using diode laser and Its performance
(© 2009 Journal of Bangladesh Academy of Sciences, 2009) Abedin, Kazi M; Habib, M Ahasan; Wahadoszamen, M; Talukder, Aminul I; Haider, A F M Yusuf; Department of Mathematics and Natural Sciences
We constructed a laser Raman system using a commercially available infrared diode laser. The diode laser is used without any temperature controller in a stabilized power supply. Good quality Raman spectra of sufficient wavelength resolution were obtained for a variety of chemicals and products, including solid samples. Raman spectra of several edible oils and ghee were also obtained and these were found to be largely free of fluorescence. Finally, Raman spectra of an artificial sweetener and a pharmaceutical product were obtained, showing the feasibility and reliability of the present Raman system in real-life situation.
Elemental profiling of surface water around Dhaka city by laser induced breakdown spectroscopy
(© 2009 Journal of Bangladesh Academy of Sciences, 2009) Ahmed, MF; Abedin, KM; Sadat, ME; Talukder, AI; Wahadoszamen, M; Haider, A F M Yusuf; Department of Mathematics and Natural Sciences
Using the technique of Laser Induced Breakdown Spectroscopy (LIBS), which uses a pulsed laser to create plasma and advanced spectroscopic techniques, we analyzed the contents of surface water (river water) around the city of Dhaka. Several elements such as Li, C, Na, Mg, Al, K, Ca, Ti, Mn, Fe, Sr were identified in the water samples collected in addition to Cr, which was found at two locations at different concentrations. Chromium is a toxic element, and its presence at high concentrations is hazardous for human beings as well as the environment. Its presence in water is suspected due to the effluent discharge from the nearby tanning industries. Semi-quantitative analysis of the chromium present was performed. To our knowledge, this is the first example of the application of the LIBS technique in water analysis in Bangladesh.
Semiquantitative determination of chromium content of river bed soil of Buriganga river at different locations
(© 2010 Journal of Bangladesh Academy of Sciences, 2010) Sadat, ME; Haider, A F M Yusuf; Abedin, KM; Wahadoszamen, M; Department of Mathematics and Natural Sciences
Using the technique of Laser Induced Breakdown Spectroscopy, the chromium content of river bed sediment of the Buriganga River is determined at various locations. Hazardous element, chromium is found in addition to other elements such as calcium, magnesium, titanium, sodium etc. The source of this chromium is most likely to be the effluent discharge from the tanneries located nearby. Semi quantitative analyses showed the relative abundances of Cr, Mg, and Ca in the river bed sediment at Kamrangir Char and Shoari Ghat locations are in the ratios of 1:9:23 and 1:11:17, respectively.
Detection of multiple elements in coal samples from Bangladesh by laser-induced breakdown spectroscopy
(© 2011 Elsevier Ltd., 2011-11) Haider, A F M Yusuf; Rony, M.A.; Lubna, R.S.; Abedin, K.M.; Department of Mathematics and Natural Sciences
Laser-induced breakdown spectroscopy (LIBS) was used to analyze the coal samples from the Barapukuria coal mine of Bangladesh and coal from eastern India. Besides the major elements carbon and silicon, a number of minor and trace elements, such as iron, titanium, aluminum, calcium, sodium, copper, zirconium, neodymium, ytterbium, cerium, samarium, dysprosium and gadolinium were identified. In earlier work some researchers identified the lines around 279 and 280 nm as due to Mg II rather than Yb III. The reasons for identifying these two lines as due to ytterbium in the present work are explained. The detection of multiple elements in one experiment in a commonly used fuel demonstrated the versatility and multi-elemental capability of LIBS.
Elemental profiling and identification of eco-toxic elements in agricultural soil by laser-induced breakdown spectroscopy
(© 2013 Science and Education Publishing, 2013-05) Haider, A F M Yusuf; Kabir, Firoza; Ullah, M. Hedayet; Khan, Z.H.; Abedin, Kazi M.; Department of Mathematics and Natural Sciences
Laser induced breakdown spectroscopy (LIBS) was used to determine the elemental content and to detect probable eco-toxic elements in agricultural soil in Gazipur, Bangladesh (latitude: 24.0958° N, longitude: 90.4125° E). Soil samples were collected from three experimental plots of Bangladesh Rice Research Institute (BRRI), Gazipur and from a fallow land in the same area where no crop has been produced for a long time. This land is believed to be contaminated by the affluent discharged from nearby industries. Rice and husk samples were also collected from one of the experimental plots. Several elements such as Ni, Cu, Zn, Fe, Ca, Al, Si, Sn, Na, K, Ti, Mn, Li, Mo, Co were identified in the soil samples of the three experimental plots. Rice and husk samples also have the same elements including Sr, P, C and Mg. The LIBS study of the soil of the fallow land confirms the presence of the toxic element Cd along with all the elements found in the soil samples of the experimental plots. The sample from the fallow land from Gazipur was also analyzed for Cd by atomic absorption spectroscopy (AAS). The presence of 6.5 ppm of Cd in this fallow land above the tolerance limit (3 ppm) is supposedly the main reason for barrenness of the fallow land in the present case.
Computer simulation of Fresnel diffraction from rectangular apertures and obstacles using the Fresnel integrals approach
(© 2005 Elsevier Ltd., 2007-03) Abedin, Kazi Monowar; Islam, M.R.; Haider, A F M Yusuf; Department of Mathematics and Natural Sciences
In this paper, we describe a new computer simulation technique of generating Fresnel diffraction images from rectangular apertures of arbitrary dimensions by using Fresnel integrals instead of the more common fast Fourier transform methods. The simulation can be performed in almost any PC using the software MATLAB. Diffraction images can be generated for any wavelength of light and for any aperture-screen and aperture-source distances. Images for rectangular obstacles can also be simulated. Details of the algorithm and program are presented, as well as the interesting insights than can be gained from using the program. Finally, it is shown that the simulated images reduce to the simple Fraunhofer diffraction patterns for certain limiting situations.
Determination of ratio of unsaturated to total fatty acids in edible oils by laser Raman spectroscopy
(© 2009 Asian Network for Scientific Information, 2009) Farhad, S. Farid Uddin; Abedin, K.M.; Islam, M. Rafiqul; Talukder, Aminul I.; Haider, A F M Yusuf; Department of Mathematics and Natural Sciences
In this study, a homemade laser Raman spectrometer was used to examine the Raman spectra of different edible oils, such as canola, corn, soybean, sunflower, palm and coconut oils. To avoid severe fluorescence effects which tend to mask the weak Raman lines, Raman bands in the 2800-3200 cm-1 region resulting from unsaturated and saturated carbon bonds in the fatty acids were chosen and measured the TUSFA/TFA (total unsaturated fatty acid/total fatty acid content) ratios of the various samples. Good correlation of the ratios of TUSFA/TFA of different edible oils with that calculated from manufacturers data was obtained, enabling us to measure unsaturation/total fatty acids ratio quickly and easily for any unknown oils and hence the measure the degree of possible adulteration.
Elemental profiling and determination of Ti content of the beach sand samples of Bangladesh using LIBS technique
(© 2010 Elsevier Ltd., 2010-09) Haider, A F M Yusuf; Wahadoszamen, Md; Sadat, M. E.; Abedin, Kazi Monowar; Talukder, A.I.; Department of Mathematics and Natural Sciences
Laser-induced breakdown spectroscopic technique was used to study the elemental profile of beach sand samples of Bangladesh. Apart from Silicon, which is the main elemental constituent of sand, the presence of Li, Na, Mg, Al, Cl, K, Ca, Ti, Cr, Mn, Fe, Zr, Sr, Ba, Te and Zn was identified in the beach sand samples. In addition to the qualitative analyses, quantitative analyses of a particular element Titanium (Ti) has been done. The result shows the presence of (2.98±0.46)% of Ti by weight of the beach sand sample from Himchhori, Chittagong. It was determined by using six calibration curves drawn for six emission lines of TiI (489.991, 498.1732, 499.107, 499.951, 503.591, 506.466 nm) by standard analyte addition method. The limit of detection (LoD) for this six calibration curves varied from 0.14 to 0.3% by weight.
Power dependence of size of laser ablated colloidal silver nanoparticles
(© 2010 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2010-11) Talukder, A. I.; Sultana, Parvin; Haider, A F M Yusuf; Wahadoszamen, Md; Abedin, Kazi Monowar; Farhad, S.F.U.; Department of Mathematics and Natural Sciences
Silver nanoparticles have been produced by laser ablation of silver metal in nanopure water without any chemical additives. It has been observed that laser power has a control over the size of the nanoparticles. Increasing laser power shows a clear blue shift in the absorption peak of fabricated nanoparticles indicating that the average size of the particles decreases with increasing laser power. Ablation for longer period reduces the average size of nanoparticles which is attributed to the re-ablation of fabricated nanoparticles. A good correlation has been observed between the peak of the absorption spectrum measured by UV-VIS spectroscopy and the average particle size measured by scanning electron microscope imaging method. The value of the coefficient of correlation is determined to be 0.965.
Identification of multiple rare earths and associated elements in raw monazite sands by laser-induced breakdown spectroscopy
(© 2010 Elsevier Ltd., 2011-02) Abedin, K.M.; Haider, A F M Yusuf; Rony, M.A.; Khan, Z.H.; Department of Mathematics and Natural Sciences
Laser-induced breakdown spectroscopy (LIBS) is an emerging and promising tool for rapid and efficient elemental analysis. We used the LIBS technique to analyze the raw monazite sands collected from the beaches in southern Bangladesh. We have detected a number of rare earths (lanthanides) such as cerium, lanthanum, praseodymium, neodymium, yttrium, ytterbium, gadolinium, dysprosium and erbium, in addition to other metallic elements such as zirconium, chromium, titanium, magnesium, manganese, niobium and aluminum. To the best of our knowledge, this is the first time multiple rare earths have been identified in a natural mineral by LIBS.
Fabrication of gold nanoparticles in water by laser ablation technique and their characterization
(© 2011 Springer-Verlag., 2011-11) Haider, A F M Yusuf; Sengupta, S.; Abedin, Kazi Monowar; Talukder, Aminul; Department of Mathematics and Natural Sciences
A colloidal solution of gold nanoparticles in deionized nanopure water was produced by laser ablation technique without the use of any chemical/surfactant. Spectral characterization and morphological studies of these nanoparticles were carried out by UV-Vis Spectroscopy and Scanning Electron Microscopy, respectively. A number of variables of the ablating laser pulse have been used to control the size of the fabricated nanoparticles. Excellent correlation between ablating laser pulse parameter and optical and morphological parameters of the gold colloids were obtained. The peak of the extinction spectra shows a monotonic blue shift for laser fluence of 410 J/cm 2 and above. Below this the extinction peak remains fairly constant in wavelength. Blue shifts of the extinction spectra were also observed with increasing re-ablation time of previously ablated gold colloids. Possible explanations of all these observations are discussed.
Determination of Ca content of coral skeleton by analyte additive method using the LIBS technique
(© 2012 Elsevier Ltd., 2012-09) Haider, A F M Yusuf; Khan, Z.H.; Department of Mathematics and Natural Sciences
Laser-induced breakdown spectroscopic (LIBS) technique was used to study the elemental prole of coral skeletons. Apart from calcium and carbon, which are the main elemental constituents of coral skeleton, elements like Sr, Na, Mg, Li, Si, Cu, Ti, K, Mn, Zn, Ba, Mo, Br and Fe were detected in the coral skeletons from the Inani Beach and the Saint Martin's island of Bangladesh and the coral from the Philippines. In addition to the qualitative analysis, the quantitative analysis of the main elemental constituent, calcium (Ca), was done. The result shows the presence of (36.15 ± 1.43)% by weight of Ca in the coral skeleton collected from the Inani Beach, Cox's Bazar, Bangladesh. It was determined by using six calibration curves, drawn for six emission lines of Ca I (428.301 nm, 428.936 nm, 431.865 nm, 443.544 nm, 443.569 nm, and 445.589 nm), by standard analyte additive method. Also from AAS measurement the percentage content of Ca in the same sample of coral skeleton obtained was 39.87% by weight which compares fairly well with the result obtained by the analyte additive method.
Elemental analyses and determination of lead content in kohl (stone) by laser-induced breakdown spectroscopy
(© 2012 Society for Applied Spectroscopy, 2012-04) Haider, Abul Fazal Mohammed Yusuf; Lubna, Rebeka Sultana; Abedin, Kazi Monowar; Department of Mathematics and Natural Sciences
Elemental analyses of kohl (stone) samples collected from three different parts of the world were performed using laser-induced breakdown spectroscopy (LIBS). The analyses indicated that lead (Pb), copper (Cu), silver (Ag), iron (Fe), calcium (Ca), aluminum (Al), silicon (Si), and sodium (Na) were present in all the kohl samples. In addition to these elements, the sample from Madina, Kingdom of Saudi Arabia (KSA), contained the elements tin (Sn), zirconium (Zr), and antimony (Sb). The sample from Mount Toor, Egypt, also contained Sn. Also, quantitative analysis for lead was carried out by the standard addition method using the LIBS technique. The result showed the presence of 14.12 ± 0.28% by weight of Pb in the sample from Madina, which compares well with the measurement done using atomic absorption spectroscopy (AAS) (13.31 ± 0.46%). The standard addition method used three calibration curves drawn for three emission lines of the LIBS spectra of Pb. The limits of detection (LoD) for these calibration curves varied from 0.27% to 1.16% by weight. The lead contents of the samples from Mount Toor and the local market of Bangladesh were also measured by the AAS technique, and the results were 14.61 ± 0.48% and 8.98 ± 0.35% by weight, respectively. The reason for determining only the lead content in kohl, which may be used as an eye cosmetic, is the adverse effect that lead has on health.
Determination of the ash content of coal without ashing: a simple technique using laser-induced breakdown spectroscopy
(© 2013 American Chemical Society, 2013-07-18) Haider, A F M Yusuf; Rony, M. A.; Abedin, K. M.; Department of Mathematics and Natural Sciences
The bituminous coal samples were analyzed using the technique of laser-induced breakdown spectroscopy (LIBS). The fraction of the ash content of the coal was spectroscopically determined by a technique requiring only two measurements of the LIBS spectrum of the coal, and the results were compared to the ash fraction determined by actual ashing of the coal in a furnace. An excellent correlation (r = 0.99) was obtained between the spectroscopically determined ash fraction and the fraction of ash content determined by actual ashing of the coal. This excellent coefficient of correlation provides sufficient confidence in the measurement of the ash content by this simple and quick method using the LIBS technique.
Detection of trace amount of arsenic in groundwater by laser-induced breakdown spectroscopy and adsorption
(© 2014 Optics and Laser Technology, 2014) Haider, A F M Yusuf; Ullah, M. Hedayet; Khan, Zulfiqar H; Kabir, Firoza; Abedin, Kazi Monowar; Department of Mathematics and Natural Sciences
LIBS technique coupled with adsorption has been applied for the efficient detection of arsenic in liquid. Several adsorbents like tea leaves, bamboo slice, charcoal and zinc oxide have been used to enable sensitive detection of arsenic presence in water using LIBS. Among these, zinc oxide and charcoal show the better results. The detection limits for arsenic in water were 1 ppm and 8 ppm, respectively, when ZnO and charcoal were used as adsorbents of arsenic. To date, the determination of 1 ppm of As in water is the lowest concentration of detected arsenic in water by the LIBS technique. The detection limit of As was lowered to even less than 100 ppb by a combination of LIBS technique, adsorption by ZnO and concentration enhancement technique. Using the combination of these three techniques the ultimate concentration of arsenic was found to be 0.083 ppm (83 ppb) for arsenic polluted water collected from a tube-well of Farajikandi union (longitude 90.64, latitude 23.338 north) of Matlab Upozila of Chandpur district in Bangladesh. This result compares fairly well with the finding of arsenic concentration of 0.078 ppm in the sample by the AAS technique at the Bangladesh Council of Scientific and Industrial Research (BCSIR) lab. Such a low detection limit (1 ppm) of trace elements in liquid matrix has significantly enhanced the scope of LIBS as an analytical tool.
Radiative lifetime measurement of excited neutral nitrogen atoms by time resolved laser-induced breakdown spectroscopy
(© 2014 Royal Society of Chemistry, 2014-08) Haider, A F M Yusuf; Ira, Mehera Kamal; Khan, Z. H.; Abedin, K. M.; Department of Mathematics and Natural Sciences
Lifetimes of the excited 2P2 (3P) 3p 4S3/2 level of a nitrogen atom corresponding to transitions to different lower states have been estimated by measuring the line intensity of a transition as a function of the delay time between the Q-switching of the laser and the gating of the window of the ICCD. This novel time resolved laser-induced breakdown spectroscopic technique is explained in the paper. The lifetimes of the upper level 2P2 (3P) 3p 4S3/2 corresponding to the three transitions to 2P 2 (3P) 3s 4P1/2 (742.346 nm), 2P2 (3P) 3s 4P3/2 (744.27 nm) and 2P2 (3P) 3s 4P5/2 (746.851 nm) were measured by this technique. The corresponding average lifetimes (τ) of these transitions were 199 ns, 105 ns and 68 ns. These values compare pretty well with the calculated lifetimes of 203.8 ns, 96.7 ns and 59.2 ns for the above three transitions as reported by Hibbert et al. The plasma temperature (atomic excitation temperature) decay time was found to be 1133 ns. This novel technique of estimating the lifetime of an excited state of an atom/ion is yet another very useful application of LIBS as a versatile analytical tool.
Laser Raman spectroscopy with different excitation sources and extension to surface enhanced raman spectroscopy
(© 2015 Hindawi Publishing Corporation, 2015) Wahadoszamen, Md; Haider, A F M Yusuf; Rahaman, Arifur; Hoque, Nabil Md. Rakinul; Talukder, Aminul I; Abedin, Kazi Monowar; Department of Mathematics and Natural Sciences
A dispersive Raman spectrometer was used with three different excitation sources (Argon-ion, He-Ne, and Diode lasers operating at 514.5 nm, 633 nm, and 782 nm, resp.). The system was employed to a variety of Raman active compounds. Many of the compounds exhibit very strong fluorescence while being excited with a laser emitting at UV-VIS region, hereby imposing severe limitation to the detection efficiency of the particular Raman system. The Raman system with variable excitation laser sources provided us with a desired flexibility toward the suppression of unwanted fluorescence signal. With this Raman system, we could detect and specify the different vibrational modes of various hazardous organic compounds and some typical dyes (both fluorescent and nonfluorescent). We then compared those results with the ones reported in literature and found the deviation within the range of ±2 cm-1, which indicates reasonable accuracy and usability of the Raman system. Then, the surface enhancement technique of Raman spectrum was employed to the present system. To this end, we used chemically prepared colloidal suspension of silver nanoparticles as substrate and Rhodamine 6G as probe. We could observe significant enhancement of Raman signal from Rhodamine 6G using the colloidal solution of silver nanoparticles the average magnitude of which is estimated to be 103.
Electron paramagnetic resonance spectra of Fe2+ and Fe3+ ions in SrO: evidence for off-centre displacement of Fe2+ ions
(© 1978 Journal of Physics C: Solid State Physics, 1978) Edgar, A; Haider, A F M Yusuf; Department of Mathematics and Natural Sciences
The electron paramagnetic resonance (EPR) spectra of Fe2+ and Fe3+ ions in single crystals of SrO are reported. Fe3+ ions occupy sites of orthorhombic symmetry and their EPR spectra have been fitted with an S=5/2 spin-Hamiltonian in which the dominant second-order terms have coefficient values of B20=(884.7+or-0.3)*10-4 cm-1 and B22=(-422.0+or-0.5)*10-4 cm-1. Fe2+ ions occur at sites of trigonal symmetry, and the single observed resonance line may be described by a spin-Hamiltonian with S'=1/2, gperpendicular to =0, g/sub ///=3.992+or-0.005 and A/sub ///(Fe57)=30.2+or-0.6*10-4 cm-1. Variable temperature experiments indicate that the Fe2+ resonance occurs between the two levels of a doublet lying 12+or-1 cm-1 above a ground state singlet. A lattice distortion calculation, based on a model of polarisable point ions, and which incorporates the crystal field stabilisation energy, is applied to the cases of Fe2+ and Mn2+ ions substituted into alkaline earth oxide host lattices. The calculation is used to support an interpretation of the spectroscopic data for SrO:Fe in which the trigonal Fe2+ site arises from an off-centre displacement of the Fe2+ ion along a (111) axis.

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