Investigations on SHG properties of LiNbO 3 /PMMA nanocomposites
- PDF / 2,941,262 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 37 Downloads / 183 Views
Investigations on SHG properties of LiNbO3/PMMA nanocomposites C. Debnath1,2 · Sunil Verma1,2 · S. Kar1 · K. S. Bartwal1,2 · V. S. Tiwari1,2 · A. K. Karnal1,2 Received: 21 April 2020 / Accepted: 6 July 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract An organic–inorganic nanocomposite (LN/PMMA) was prepared using nearly stoichiometric lithium niobate (LiNbO3; LN) nanoparticles dispersed homogeneously into a polymer matrix, poly(methyl methacrylate) (PMMA). This composite is having anisotropic LN nanocrystals, oriented randomly in an isotropic host matrix of PMMA. So far, to the best of our knowledge, different nonlinear optical (NLO) properties have been studied for organic–inorganic nanocomposites in thin film and waveguide form, the thickness of which was in micron and submicron order. In this article, for the first time, we have presented SHG properties of thick LN/PMMA nanocomposites of thickness, 0.1 mm and above. LN/PMMA nanocomposite samples of different thickness and different concentrations of LN nanoparticles were fabricated. The attenuation coefficients of these samples, measured at laser wavelengths of 1064 nm and 532 nm, show a deviation from Beer-Lambert law. In the LN/PMMA nanocomposite, the effect of the randomly oriented LN nanoparticles on second harmonic generation (SHG) has been studied as a function of (a) input pulse energy of the fundamental laser (1064 nm), (b) LN nanoparticle concentration and (c) the sample thickness. The net effect was found to be the result of two competitive phenomena; harmonic generation and different losses from LN nanoparticles. Thermal effects at high input pulse energy also play important role in second harmonic generation. Through these studies, one can get an idea about the collective behavior of LN nanoparticles, particularly effect on their linear and nonlinear optical properties, and how they can be dispersed in isotropic host matrices (to different concentration levels) to achieve the desired NLO effect. Keywords Lithium niobate · Nanoparticles · Polymers · Nanocomposites · Optical properties · Second harmonic generation
1 Introduction Lithium niobate (LiNbO3; LN) has perovskite crystal structure and exhibits several important physical properties, such as ferroelectric, piezoelectric, pyroelectric, electro-optic, photoelastic, photorefractive, and nonlinear optical (NLO) properties with high figure of merit for photonic applications [1–3]. Due to high NLO coefficient, LN is an attractive material in the field of frequency conversion, nonlinear correlation spectroscopy, optical isolators, modulators, data storage, all-optical signal processing, ultrafast switching, dispersion compensation, quantum optics etc.[4, 5]. Due to this reason, LN is an extensively studied material in bulk * Sunil Verma [email protected]; [email protected] 1
Laser and Functional Materials Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, India
Homi Bhabha National Institute, BARC Training School Complex, Anushakti Nagar,
Data Loading...
