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6. The role of hydroxyl ions in the evolution of optical nonlinearity of CuO : a Z scan studyRiya Sebastian, Mohanachandran Nair Sindhu Swapna, H. V. Saritha Devi, Vimal Raj, Misha Hari, Sankaranarayana Iyer Sankararaman, 2019, original scientific article Keywords: hydroxyl ions, optical nonlinearity, Z scan, copper oxide Published in RUNG: 05.07.2022; Views: 1841; Downloads: 59 Link to full text This document has many files! More... |
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9. Optical emission diagnosis of carbon nanoparticle incorporated chlorophyll for sensing applicationsMohanachandran Nair Sindhu Swapna, RAJ VIMAL, SARITHA DEVI H V, Sankararaman S, 2019, original scientific article Abstract: Chlorophyll fluorescence (Chl F) is widely used in sensing applications to understand terrestrial vegetation
and environmental and climatic variations. The increasing rates of industrialization and carbon emission
from internal combustion engines (ICEs) pose a threat to sustainable development. This study analyses
the impact of carbon nanoparticles (CNPs) from ICEs on the optical absorption and fluorescence emission of leaf pigments. Leaf pigments without and with CNPs were subjected to UV-visible and photo-luminescence (PL) spectroscopy analyses. The field emission scanning electron microscopy and high-resolution transmission electron microscopy images of CNPs showed their morphology. The Jablonski diagram of the CNP-incorporated chlorophyll system helped in understanding the fluorescence emission,internal conversion, and the exchange of energy between them. The variations in (i) total chlorophyll, (ii)
optical absorbance by total chlorophyll, (iii) PL emission peak (at 675 nm and 718 nm) intensities for different excitation wavelengths, and (iv) normalized absorbance at the PL emission peaks with different CNP concentrations were analysed by dividing into three regions. In Region I (0–0.625 mg ml−1 ), the
radiative component dominated the nonradiative component as a result of energy transfer from CNPs to chlorophyll. In Region II (0.625–1.2 mg ml−1 ), the increase in CNP concentration initiated diffusion into chloroplasts, resulting in the increase in the nonradiative part of total energy and decrease in PL peak
intensity. In Region III (1.2–2.5 mg ml−1
), the energy absorbed by the CNPs dissipated more nonradiatively, leading to a slow rate of increase in the radiative part. The visual response of PL emission, color purity,
and the distribution of the emitted energy over the spectrum studied with the help of CIE plots, power spectrum, and confocal fluorescence microscopy revealed the fluorescence emission in the red region. This study suggests the possibility of employing Chl F in agricultural, environmental, and biological fields
for sensing applications. Keywords: carbon nanoparticle, optical emission, fluorescence Published in RUNG: 05.07.2022; Views: 1877; Downloads: 0 This document has many files! More... |
10. Speckle interferometric investigation of argon pressure-induced surface roughness modifications in RF-sputtered MoO[sub]3 filmS. Soumya, R. Arun Kumar, S. Sreejyothi, Vimal Raj, Mohanachandran Nair Sindhu Swapna, Sankaranarayana Iyer Sankararaman, 2021, original scientific article Abstract: Film quality analysis is of more considerable signifcance due to its diversifed applications in various felds of technology.
The present work reports the speckle interferometric analysis of the argon pressure-induced surface roughness modifcations
of RF sputtered MoO3 flms. The paper suggests a new method of surface quality analysis of thin flms through a parameter
δ, which is the diference between the initial and fnal inertia moment values in the study of the thermal-induced dynamic
speckle pattern. The limitations of root mean square surface roughness analysis of the atomic force microscopic image of the
flms is also exemplifed. The research suggests that argon pressure plays a vital role in the surface property of RF sputtered
flms and also that the dynamic speckle analysis can give precise information about the quality of flms. The contour plot of
particle displacement vector under thermal stress, suggests the degree of uniformity in the distribution of particles in the flm. Keywords: speckle pattern interferometry, time history of speckle pattern, cross correlation, inertia moment Published in RUNG: 04.07.2022; Views: 1981; Downloads: 0 This document has many files! More... |