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Sajan D. George
Manipal University
77Publications
13H-index
454Citations
Publications 77
Newest
#1K M Muhammed Shameem (Manipal University)H-Index: 4
#2V. S. Dhanada (Manipal University)H-Index: 1
Last.V. K. Unnikrishnan (Manipal University)H-Index: 10
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Abstract There are a number of analytical techniques used to study material related problems. Most of them imply experimental determination of parameters and functions by means of which elemental, optical and other properties of materials can be described. Laser Induced Breakdown Spectroscopy (LIBS) and Raman spectroscopy are highly complementary spectroscopic techniques used for lab, in-situ, and remote analyses of materials. The LIBS-Raman system provides further information compared to other ...
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#1Sajan D. George (Manipal University)H-Index: 13
#2Santhosh Chidangil (Manipal University)H-Index: 9
Last.Deepak MathurH-Index: 29
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Recent work is summarized that shows how microbubbles may have potential utility in biomedical situations as (i) highly localized generators of intense white light in an aqueous environment, (ii) disruptors of matter in aqueous solution, (iii) essential precursors in laser-writing structures on substrates on which biological cells can be spatially aligned, and (iv) mediators in the fabrication of hierarchical nanostructures that enhance signals in biological Raman spectroscopy. Indeed, microbubb...
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#1K.S. Choudhari (Manipal University)H-Index: 9
#2Suresh D. Kulkarni (Manipal University)H-Index: 10
Last.Sajan D. George (Manipal University)H-Index: 13
view all 6 authors...
Abstract Highly-ordered nanoporous anodic alumina (NAA) with varying thicknesses were prepared by changing the anodization time from 10 min to 10 h, using a two-step electrochemical oxidation in oxalic acid. Three optical characterizations, namely, Ultraviolet–Visible–Near Infrared (UV–VIS–NIR), Photoluminescence (PL), and Reflective interference spectra were used to measure NAA’s thicknesses. All three types of spectra displayed oscillations due to the optical interferences which were used for ...
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#1K.S. Choudhari (Manipal University)H-Index: 9
#2Deepak Hebbar N (Manipal University)H-Index: 1
Last.Sajan D. George (Manipal University)H-Index: 13
view all 5 authors...
Microwave-assisted solution technique (MAST) was used for the homogeneous doping of Cr3+ in nanoporous anodic alumina (NAA) which when heat-treated transforms into nanoporous ruby. The rise in annealing temperature led to the phase transition in the sequence: amorphous- δ- θ- α-alumina as evidenced by XRD. The dopant was homogenously distributed as seen from the elemental mapping and the Cr3+ content was 0.5 at%. Diffuse reflectance spectroscopy (DRS) displayed the characteristic blue and green ...
1 CitationsSource
#1Shivanand H. Nannuri (Manipal University)H-Index: 1
#2Amiya Ranjan Samal (Manipal University)H-Index: 1
Last.Sajan D. George (Manipal University)H-Index: 13
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Abstract In this work, we show the influence of Cr3+ ion concentration (1–7 mol%) on the crystalline phase and shape, laser power dependent luminescence response, and temperature response in physiological temperature range for NaYF4:Yb, Er (Y: 88%, Yb: 10% and Er: 2%) submicron crystals prepared via hydrothermal method. The atomic absorption spectral studies indicate the successful incorporation of the Cr3+ ions into NaYF4:Yb, Er (Y: 88%, Yb: 10% and Er: 2%). The detailed investigation on the cr...
1 CitationsSource
#1Sajan D. GeorgeH-Index: 13
#2Santhosh ChidangilH-Index: 9
Last.Deepak MathurH-Index: 29
view all 3 authors...
Recent work is summarized that shows how microbubbles may have potential utility in biomedical situations as (i) highly localized generators of intense white light in an aqueous environment, (ii) disruptors of matter in aqueous solution, (iii) essential precursors in laser-writing structures on substrates on which biological cells can be spatially aligned, and (iv) mediators in the fabrication of hierarchical nanostructures that enhance signals in biological Raman spectroscopy. Indeed, microbubb...
#1Shivanand H. Nannuri (Manipal University)H-Index: 1
#2Suresh D. Kulkarni (Manipal University)H-Index: 10
Last.Sajan D. George (Manipal University)H-Index: 13
view all 5 authors...
The role of post synthesis annealing at different temperatures (200–600 °C) on the structural as well as luminescence properties of NaY80%F4:Yb17%,Er3% prepared via a coprecipitation method was found to change the structure from a cubic to hexagonal phase with a concomitant increase in upconversion luminescence by 12 times for the green region and 17 times for the red region. Addition of the Cr3+ ions (5–20 mol%) into the host followed by post annealing at 200–600 °C causes that the samples to e...
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#1Shilpa Thippeshappa (Manipal University)
#2Sajan D. George (Manipal University)H-Index: 13
Last.Abdul Ajees Abdul Salam (Manipal University)H-Index: 4
view all 6 authors...
Laser-induced crystallization is emerging as an alternative technique to crystallize biomolecules. However, its applications are limited to specific small molecules and some simple proteins, possibly because of the need to use high-intensity, pulsed lasers and relatively long laser irradiation time. Both these factors tend to denature biological molecules. If the laser-intensity and time required to crystallize biomolecules were to be reduced, laser-induced crystallization may well become of wid...
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#1K.S. Choudhari (Manipal University)H-Index: 9
#2Suresh D. Kulkarni (Manipal University)H-Index: 10
Last.Sajan D. George (Manipal University)H-Index: 13
view all 4 authors...
We report on the photoluminescence (PL) enhancement and morphological properties of highly ordered Nanoporous anodic alumina (NAA) fabricated by two-step anodization for 2–10 h at 5 °C and 25 °C anodization temperatures. Structural features and pore arrangements of NAA were characterized. Pore-properties such as pore-diameter, porosity and growth rate showed an increase with rising in temperature whereas pore-wall thickness and barrier layer thickness decreased, however, interpore distance and p...
4 CitationsSource
#1Jijo Easo George (Manipal University)H-Index: 4
#2V. K. Unnikrishnan (Manipal University)H-Index: 10
Last.Sajan D. George (Manipal University)H-Index: 13
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Abstract The ability to fingerprint a few molecules via surface enhanced Raman scattering (SERS) continues to be of considerable utility in diverse fields encompassing physics, chemistry, materials sciences, nanotechnology, biomedicine, and environmental engineering. However, the development of facile and low cost approaches towards the fabrication of flexible substrates with very high SERS signal enhancement remains a challenge. Compared to conventional plasmonic-based sensors, a superhydrophob...
4 CitationsSource
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