Wide band gap Oxide based diluted magnetic semiconductors (ODMS) exhibit unique magnetic, magneto-optical and magneto-electrical effects and can be exploited as spintronic devices. Theoretical studies of transition metal (TM) doped zinc oxide which belongs to these class of materials has been attracting significant research interest in the recent years. In this paper, the electronic band structures, and band gap energies of ZnO doped with transition metal have been analyzed by ab initio calculations based on the density functional theory using quantum espresso PWscf code. For the band gap calculations, we have used both local density approximation (LDA) and generalized gradient approximation (GGA). The magnetic and optical properties of the materials have been studied using the above method. For all the theoretical calculations, the model structures of transition metal-doped ZnO were constructed by using the 16 atom supercell with one Zn atom replaced by a transition metal atom. The results are useful in understanding the band gap variations with doping and other related properties in oxide based diluted magnetic semiconductors such as ZnO.
The electronic, magnetic and optical properties of rutile Ti1-xTMxO2 (where TM: Ni, Cu and x = 0.25) have been investigated by the density functional theory with the plane wave self consistent field method. For the calculation of exchange correlation potential, the local density approximation along with Hubbard correction (LDA +U) was used. Electronic, magnetic and optical properties were calculated using 12 atoms supercell of rutile TiO2 with one Ti atom replaced by a dopant transition metal atom. The band structure of doped rutile phase indicates the reduction of band gap leading to improvement in the photocatalytic properties of TiO2 as well as enhancement in its magnetic properties. The observed magnetism is explained on the basis of spin polarization of d states of Ti with dopants. Optical calculations by full potential, linear augmented plane wave plus local orbital (FP-LAPW+lo) method with ELK code established the presence of optical transitions in the visible light region. These theoretical calculations gave a meaningful information and excellent prediction to develop TiO2 for spintronics applications and photocatalytic applications in the visible region.
The demand for highly sensitive and reliable sensors to assess the refractive index of liquid get many applications in
chemical and biomedical areas. Indeed, the physical parameters such as concentration, pressure and density, etc., can be
found using the refractive index of liquid. In contrast to the conventional refractometer for measurement, optical fiber
sensor has several advantages like remote sensing, small in size, low cost, immune to EMI etc., In this paper we have
discussed determination of refractive index of sugar solution using optical fiber. An intensity modulated low cost plastic
fiber optic refractive index sensor has been designed for the study. The sensor is based on principle of change in angle
of reflected light caused by refractive index change of the medium surrounding the fiber. The experimental results
obtained for the sugar solution of different refractive indices prove that the fiber optic sensor is cable of measuring the
refractive indices as well as the concentrations.
This paper describes the work of some SPIE student chapter members to create interest in students on optics by teaching students in upper primary schools in and around college premises on fundamental concepts of light such as reflection, refraction, diffraction, etc. This paper discusses about how the outcome based education (OBE) is helpful in learning optics interesting rather than the traditional way of learning. In order to achieve this, students are divided into groups and conducted a workshop. Student learning outcomes were assessed at the end of the program. The program is useful to us to improve our understanding of how students learn light - related principles and provide evidence of the learning outcomes on the subject. Our research established that students in every classroom learned optics concepts, uncovered student ideas about optics, and identified ways to support and supplement the curriculum for use in classrooms.
The broad objective of this paper is to study the surface of the corroded metals by using proximity sensor which works
on the principle of light scattering by objects. The present work discussed a simple low cost sensor design making use
of plastic optical fiber. The sensor used is insensitive to source fluctuation and can detect surface roughness of the
metals. The average surface roughness of the samples in different concentrations of acidic medium has been studied
using the sensor. The reflected light intensity from the surface of sample metals was collected and measured as a
function of lateral distance to estimate the roughness of the surface. The results have been compared with the stylus
measurements.
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