G. Vinitha

Bio: G. Vinitha is an academic researcher from VIT University. The author has contributed to research in topics: Single crystal & Crystal. The author has an hindex of 23, co-authored 251 publications receiving 2106 citations. Previous affiliations of G. Vinitha include B. S. Abdur Rahman University & Anna University.

Non linear optical studies on semiorganic single crystal: L-arginine 4-nitrophenalate 4-nitrophenol dihydrate (LAPP)

Abstract: L -arginine 4-nitrophenalate 4-nitrophenol dihydrate (LAPP) has been synthesized and grown by solution growth at room temperature using deionized water as a solvent. The various functional groups of the sample were identified by Fourier transform infra-red and Fourier transforms – Raman spectroscopic analyses. The Laser damage threshold of LAPP has been studied. Refractive index of LAPP single crystal was measured using Metricon prism coupler Instrument. The etching studies were carried out to study the quality of the grown crystals. The third order nonlinear optical properties of LAPP sample was analyzed by the Z-scan technique using 532 nm diode pumped CW Nd: YAG laser. The LAPP material exhibits negative optical nonlinearity. The results show that LAPP sample has potential applications in nonlinear optics and it can be exploited for optical limiting or switching.

A green strategy to synthesize environment friendly metal oxide nanoparticles for potential applications – a review

Abstract: Chemical reducing and capping reagents are largely used in synthesizing metal oxide nanoparticles which limits the biomedical applications. Researchers have recently found out the eco-friendly technique of green synthesis which enhances the unique physical and chemical properties of nanomaterials. In this critique, we discuss green route to synthesize metal oxide nanoparticles and its significant applications in various fields of energy and environment, aerospace, medicine, biotechnology, etc.This study arouses to provoke new research design of approach to synthesize nanoparticles for various technological applications. In this review, most of the metal oxides nanoparticles with different plant extract with enhanced properties for its potential applications are discussed which confirms plant extracts as a potential candidate to be used as reducing and capping agent.

Investigations on 4-methyl benzophenone (4MB) single crystal grown by Czochralski method and its characterization

Abstract: Bulk size 4-methyl benzophenone (4MB) single crystals have been grown by Czochralski method in a period of 8 h. The unit cell parameters of the grown crystals were confirmed by single crystal X-ray diffraction analysis. The lower UV cut-off wavelength of 4MB crystal was studied by UV–Vis NIR spectrum analysis and the cut-off wavelength was found to be 379 nm. The FTIR spectrum confirms the presence of different functional groups present in the crystal. The luminescence properties of 4MB single crystal were described by Photoluminescence spectra. Thermal stability, material decomposition and melting point of the grown crystals were determined by Thermogravimetric/differential thermal analysis measurements. The mechanical stability of the 4MB single crystal was examined using Vickers microhardness test and it was found that the crystal belongs to soft material category. Laser damage threshold measurement was carried out by using Nd:YAG laser. The nonlinear refractive index, nonlinear absorption coefficient and third order nonlinear susceptibility were measured from Z-Scan measurements. The density functional theory calculations for isolated 4MB molecule were performed with B3LYP/6-311 + + G(d,p) level. The electronic properties and polarizabilities of title molecule were calculated.

Two-photon polymerization initiators for three-dimensional optical data storage and microfabrication

Abstract: Two-photon excitation provides a means of activating chemical or physical processes with high spatial resolution in three dimensions and has made possible the development of three-dimensional fluorescence imaging, optical data storage, and lithographic microfabrication. These applications take advantage of the fact that the two-photon absorption probability depends quadratically on intensity, so under tight-focusing conditions, the absorption is confined at the focus to a volume of order λ3 (where λ is the laser wavelength). Any subsequent process, such as fluorescence or a photoinduced chemical reaction, is also localized in this small volume. Although three-dimensional data storage and microfabrication have been illustrated using two-photon-initiated polymerization of resins incorporating conventional ultraviolet-absorbing initiators, such photopolymer systems exhibit low photosensitivity as the initiators have small two-photon absorption cross-sections (δ). Consequently, this approach requires high laser power, and its widespread use remains impractical. Here we report on a class of π;-conjugated compounds that exhibit large δ (as high as 1, 250 × 10−50 cm4 s per photon) and enhanced two-photon sensitivity relative to ultraviolet initiators. Two-photon excitable resins based on these new initiators have been developed and used to demonstrate a scheme for three-dimensional data storage which permits fluorescent and refractive read-out, and the fabrication of three-dimensional micro-optical and micromechanical structures, including photonic-bandgap-type structures.

Nonlinear Optical Materials for the Smart Filtering of Optical Radiation.

Abstract: The control of luminous radiation has extremely important implications for modern and future technologies as well as in medicine. In this Review, we detail chemical structures and their relevant photophysical features for various groups of materials, including organic dyes such as metalloporphyrins and metallophthalocyanines (and derivatives), other common organic materials, mixed metal complexes and clusters, fullerenes, dendrimeric nanocomposites, polymeric materials (organic and/or inorganic), inorganic semiconductors, and other nanoscopic materials, utilized or potentially useful for the realization of devices able to filter in a smart way an external radiation. The concept of smart is referred to the characteristic of those materials that are capable to filter the radiation in a dynamic way without the need of an ancillary system for the activation of the required transmission change. In particular, this Review gives emphasis to the nonlinear optical properties of photoactive materials for the functi...

Nonlinear optical properties and applications of 2D materials: theoretical and experimental aspects

Abstract: In this review, we survey the recent advances in nonlinear optics and the applications of two-dimensional (2D) materials. We briefly cover the key developments pertaining to research in the nonlinear optics of graphene, the quintessential 2D material. Subsequently, we discuss the linear and nonlinear optical properties of several other 2D layered materials, including transition metal chalcogenides, black phosphorus, hexagonal boron nitride, perovskites, and topological insulators, as well as the recent progress in hybrid nanostructures containing 2D materials, such as composites with dyes, plasmonic particles, 2D crystals, and silicon integrated structures. Finally, we highlight a few representative current applications of 2D materials to photonic and optoelectronic devices.

Nonlinear optical properties of metal nanoparticles: a review

Abstract: Metal nanoparticles (MNPs) hold great technological promise because of the possibility of engineering their electronic and optical properties through material design. One of the effective methods to fabricate MNPs is ion implantation. In this review, recent results on the nonlinear optical properties of nanoparticles (including copper, silver, gold, and bismuth nanoparticles) doped in various bases have been discussed. Some specific optical nonlinear properties, such as nonlinear refraction, two-photon absorption, and optical limiting, for femtosecond, picosecond, and nanosecond laser pulses have also been covered. In addition to ion implantation, we have summarized several other methods for the preparation of composite materials, and Z-scan has been used to study the nonlinear optical properties of these materials.