Crystals: Dielectric crystalline solids exhibit a unique combination of optical properties, including birefringence, second (or higher) order nonlinearity, broadband transparency, high damage threshold and ion hosting capacity. Thanks to these properties, crystals play a significant role as active elements in laser and nonlinear optics technologies. We employ refractometry to accurately determine the wavelength, temperature and direction dependent refractive indices of crystals. Fed to custom computing tools and theoretical models, our data enable us to simulate several linear and nonlinear optical phenomena that are relevant to specific applications, ranging from dispersion, group-velocity and pulse-broadening effects to phase-matching conditions.
Fluids: In recent years, there is a growing interest in the replacement of solid (active or passive) photonics elements by fluids. Optofluidic devices may come at ultra-compact size and low cost, offering also unprecedented functional flexibility. On the negative side, the optical properties of liquids are severely understudied compared to their solid counterparts, such as dielectric crystals, semiconductors, glasses or polymers. Aiming to close this gap, we experimentaly determine the visible to near-infrared refractive index of various solvents. We currently emphasize on the study of ionic liquids, the physical properties of which can be tailored to suit specific applications. From a more fundamental point of view, the optical constants of fluids also relate to their molecular structure, facilitating the calculation of microscopic matterial properties (e.g., electronic polarizability, molar volume and radius) from macroscpopic reflectance measurements.
Group’s journal publications on this topic [click for more]
18 A. Mero, L. Guglielmero, F. D’Andrea, C.S Pomelli, L. Guazzelli, S. Koutsoumpos, G. Tsonos, I. Stavrakas, K. Moutzouris, A. Mezzetta. Influence of the cation partner on levulinate ionic liquids properties. Journal of Molecular Liquids 354, 118850 (2022).
9 C. Chiappe, P. Margari, A. Mazzetta, C.S Pomelli, S. Koutsoumpos, M. Papamichael, P. Giannios, K. Moutzouris. Temperature effects on the viscosity & the wavelength-dependent refractive index of imidazolium-based ionic liquids with a phosphorus-contanining anion. Phys Chem Chem Phys 19, 8201 (2017).
6 K. Moutzouris, M. Papamichael, S.C Betsis, I. Stavrakas, G. Hloupis, D. Triantis. Refractive, dispersive and thermo-optic properties of twelve organic solvents in the visible and near-infrared. Applied Physics B 116, 617 (2014).
5 E. Stoumbou, I. Stavrakas, G. Hloupis, A. Alexandridis, D. Triantis, K. Moutzouris. A comparative study on the use of the extended-Cauchy dispersion equation for fitting refractive index data in crystals. Optical and Quantum Electronics 45, 837 (2013).
4 A. Alexandridis, E. Chondrodima, K. Moutzouris, D. Triantis. A neural network approach for the prediction of the refractive index based on experimental data. Journal of Materials Science 47, 883 (2012).
3 K. Moutzouris, G. Hloupis, I. Stavrakas, D. Triantis, M.H Chu. Temperature-dependent visible to near-infrared optical properties of 8 mol% Mg-doped lithium tantalate. Optical Materials Express 1, 458 (2011).
2 K. Moutzouris, I. Stavrakas, D. Triantis, M. Enculescu. Temperature-dependent refractive index of potassium acid phthalate (KAP) in the visible and near-infrared. Optical Materials 33, 812 (2011).
Group’s conference publications on this topic [click for more]
3 K. Moutzouris, I. Stavrakas, C. Anastasiadis, D. Triantis. Theoretical study of second harmonic generation in strontium and calcium tartrato-antimonates. International Commission for Optics Topical Meeting on Emerging Trends and Novel Materials in Photonics. 7 – 9 October 2009. Delphi, Greece.