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Your search keyword '"Hegde, Vinod"' showing total 133 results
Start Over Author "Hegde, Vinod" Publication Type Academic Journals
133 results on '"Hegde, Vinod"'

27. Near-infrared and green light emission spectroscopic characteristics of Er3+ doped alumina–phosphate glasses.

Author

Hegde, Vinod, Vighnesh, K. R., Kamath, Sudha D., Viswanath, C. S. Dwaraka, Almuqrin, Aljawhara H., Sayyed, M. I., Gangareddy, Jagannath, Rajaramakrishna, R., and Keshavamurthy, K.

Subjects
GREEN light, PHOSPHATE glass, NEAR infrared radiation, OSCILLATOR strengths, GLASS structure, MONOCHROMATIC light, QUALITY factor, BRANCHING ratios
Abstract

Trivalent erbium ions doped (48 – x) AlPO4 + 15K2O + 12MgF + 20Na2O + 5NaF + xEr2O3 glass samples have been prepared utilizing the melt-quench process and studied to understand the efficacy of Er3+ ions content on physical, structural and luminescence attributes of host glass. The functional groups of the glass structure such as metaphosphate, orthophosphate and pyrophosphate have been elucidated through Fourier Transform Infrared (FTIR) spectroscopic investigation. The least-square approach was used to calculate the Judd–Ofelt parameter from the oscillator strength of the Er3+ ion transitions. The luminescence emission data captured in the visible and near-infrared (NIR) province using 380 and 980 nm excitation wavelengths. The up-conversion (recorded at the excitation at 980 nm) of 0.5 Er glass exhibited emission at 664, 550 and 488 nm wavelengths. The decay plots of the studied glass specimens were measured at 980 nm excitation. The McCumber (MC) theory has been implemented to calculate the gain coefficient of the 0.5 Er glass and flat gain curve was drawn for S-band, C-band and L-band. The attributes for optical amplification were ascertained, including the quality factor (0.85), branching ratio (1), stimulated emission cross-section (1.3 × 10–20 cm2), gain bandwidth (1.26 × 10–25 cm3) and optical gain (0.394 × 10–23 cm2 s) for 0.5 Er glass. The yellowish green light emission ability of the 0.5 Er glass after 980 nm excitation evident through CIE co-ordinates position (x 0.36, y 0.58) at 1931 CIE chromaticity diagram. The spectroscopic and luminescence results endorse that the alumino–phosphate glass specimens loaded with 0.5 mol% of Er2O3 are beneficial for NIR and green light emission applications. [ABSTRACT FROM AUTHOR]

Published
2024
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34. Spectroscopic analysis of Dy3+ in alkali-varied zinc barium borate glasses for solid-state lighting devices.

Author

Hegde, Vinod

Subjects
BORATE glass, BARIUM, SOLID-state lasers, EXCITATION spectrum, OSCILLATOR strengths, ZINC, ACTIVE medium
Abstract

In the present study, Dy3+ ion and alkali-varied borate glasses were prepared by melt quench technique for spectroscopic analysis. The refractive index and density values of the varied alkali glasses were determined, and the values were incorporated into the Judd–Ofelt (J.O) analysis. The excitation and emission spectral analysis of glasses helped to optimize the effect of Dy3+ ion concentrations on visible light emission properties of zinc barium lithium borate glasses. The FTIR analysis revealed the structural changes due to alkali ion variation in the glasses. The oscillator strength of identical absorption transitions corresponding to the absorption spectrum was calculated with the change in alkali group in the host glass. Especially, excitation spectra of the Dy3+ doped zinc barium borate glass revealed the spectral changes and its dependency on the alkali component in the host borate glasses. The calculative analysis of lasing parameters, color chromaticity index (CIE), and correlated color temperature (CCT) values disclosed the usefulness of the entitled glass as gain medium applications for solid-state laser and lighting devices. [ABSTRACT FROM AUTHOR]

Published
2023
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37. Analysis of Optical and Near-Infrared Luminescence of Er 3+ and Er 3+/ Yb 3+ Co-Doped Heavy Metal Borate Glasses for Optical Amplifier Applications.

Author

Hegde, Vinod, Devarajulu, G., Pramod, A. G., Kolavekar, Sangeeta B., Aloraini, Dalal Abdullah, Almuqrin, Aljawhara H., Sayyed, M. I., and Jagannath, G.

Subjects
OPTICAL glass, BORATE glass, OPTICAL amplifiers, YTTERBIUM, HEAVY metals, ERBIUM, LUMINESCENCE, TELECOMMUNICATION
Abstract

For the near-infrared emission, Er3+ and Er3+/Yb3+ co-activated borate based glass hosts were synthesized by the method of melting andquenching. The emission intensity was maximum for 0.5 mol% Er3+ singly activated glass in the near-infrared (NIR) region covering the telecommunication window. The 2 mol% of Yb3+ co-doping enhanced the emission gain cross-section of the glass by two times contrast to 0.5 mol% Er3+ loaded glass. This enhancement shifted to lower spectral regions when P increased from 0 to 1. The effect of Yb3+ loading on the gain cross-section of the Er3+ co-activated glasses was analyzed using the McCumber theory. The results showed that the 0.5Er2Yb glass has a flat gain in the range of 1460–1640 nm, this suggest a lower pump threshold is enough to perform the laser functioning of a 1530 nm band and optical window of telecommunication applications. [ABSTRACT FROM AUTHOR]

Published
2022
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42. Surgical nuances in the separation of craniopagus twins - Our experience and a follow up of 15 years.

Author

Pai, K. Muralidhar, Naidu, R. Chandrasekhar, Raja, A, Rai, Y S, Kumar, Niranjan, Kini, Anand, Joseph, Santhosh, Hegde, Vinod, Ballal, H S, Rao, Ramoorthi, Sharma, Saroja V, Valakatte, Vinay Kumar, and Pai K, Muralidhar

Subjects
CONJOINED twins, CEREBROSPINAL fluid, SKULL abnormalities, HUMAN abnormalities, NEUROLOGIC examination
Abstract

Craniopagus twins are conjoined twins fused at the cranium. This is the rarest anomaly seen in conjoined twins and craniopagus twins account for 2- 6% of conjoined twins. Conjoined twins are also extremely rare, with the anomaly seen in about 10-20 subjects per billion births. A female preponderance has been noted. Craniopagus twins can be classified into complete or partial, depending on whether or not they have shared dural venous sinuses. They can be further classified into angular or total depending on the alignment of the inter-twin longitudinal axis. Surgical separation of these cases can be an elective procedure or an emergency, mandated by the death of one of the twins. Surgical separation of craniopagus twins is a complex exercise needing detailed evaluation and planning. For the successful management of these twins, a multi-disciplinary approach involving neurosurgeons, plastic surgeons, anesthetists, radiologists, pediatric critical care specialists and ancillary staff is mandatory. We present a case of partially successful elective separation of partial angular craniopagus twins performed in 2002.The surviving twin was managed conservatively for a cerebrospinal fluid leak. The patient subsequently developed a pseudomeningocele, necessitating re-exploration, excision of the gliotic tissue, and repair of the dura and the overlying scalp flap. The patient has a skull defect for which cranioplasty has been deferred. The child is neurologically intact. The post-operative evaluation and the detailed periodic neurological assessment till date (with a follow up of 15 years) have been presented in this study. [ABSTRACT FROM AUTHOR]

Published
2018
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49. Proceedings of the Indian Academy of Sciences—Section A—Volume 88–1979

Author

Bhasu, V. C. Jyothi, Sathyanarayana, D. N., Patel, C. C., Namasivayam, R., Nagarajan, S., Reddy, K. Subramanyam, Naidu, P. R., Reddy, P. N. Nandi, Deshpande, D. A., Kher, V. G., Manimaran, T., Natarajam, M., Ramakrishnan, V. T., Navaneetham, N. S., Soundararajan, S., Malik, Wahid U., Goyal, R. N., Tyagi, Sudha, Basu, Gobinda, Mali, B. D., Pethe, L. D., Ramachandran, M. S., Singh, U. Chandra, Subbaratnam, N. R., Kelkar, V. K., Radhakrishnamurti, P. S., Swamy, B. R. K., Swamy, B. R. K., Gupta, S. P., Singh, P., Sane, K. V., Saxena, R. P., Srivastava, P. K., Joshi, Balawant S., and Hegde, Vinod R.

Published
1979
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