0000000000416805
AUTHOR
Guntis Liberts
Thermal imaging in artificial nonlinear media
A method has been developed to determine the temperature distribution of ferroelectric surfaces and volumes. Based on the nonlinear optical effect of second harmonic generation (SHG) in highly nonlinear ferroelectric coating, demonstration of 2D thermosensing has been performed in the wide temperature range (77 K - 600 K). Physical concept of SHG thermal imaging, design of thermosensitive coating and experimental verification of the method has been discussed.
<title>Electric-field-induced suppression of thermal lensing in ferrofluids</title>
Thermal lens measurements on the thin films of ferrofluid located between the transparent indium-thin oxide (ITO) electrodes on glass substrate has been performed. In the presence of axial electric voltage we have observed suppression of characteristic far field patterns (rings) of thermal lens replaced by moving labyrinth structures. Critical value of the suppression field, for example in kerosene based ferrofluids - 13 kV/cm, and for ionic ferrofluids - 2,5 kV/cm, has been estimated.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Thermo-Optical Investigation of Sodium-Bismuth Titanate Single Crystal and PLZT Ceramics
Thermal lensing in relaxor type ferroelectrics as a function of temperature has been investigated by using pulse/probe method. Enhanced thermo-optical (TO) properties had been observed in 3d elements (Cu, Co) doped PLZT ceramics and in sodium-bismuth titanate single crystals near phase transitions (PT). Comparison of TO signals for several doped PLZT materials reveals that 0.5 wt.% Cu doping is responsible for improved thermal lensing parameters interpreted by optimal light absorption, heat transfer and possible PT adjustment. TO experiments in sodium-bismuth titanate single crystals ([001] cut) show enhancement of TO properties in the region of PT and coexisting phases (rhombohedral and te…
Thermo-optical mirror on a free ferrofluid surface
Here we report on the first, to our knowledge, direct experimental observation of giant thermo-optical mirror effect on the free surface of ferrofluid under He-Ne laser excitation. In our experiment a slightly focused laser beam of power in mW range is incident nearly normally to the surface, and a characteristic diffraction ring pattern has been observed in reflection mode. Concave surface deformation has been clearly observed at laser irradiated spot and has been explained in terms of lubrication theory approach for laser driven thermocapillary motion in thin layer of light absorbing fluid.
<title>Nonlinear optical properties of some indandione-1,3 pyridinium betaine derivatives</title>
In this paper nonlinear optical properties of indandione-1,3 pyridinium betaine (IPB) molecule and its novel amphiphilic derivatives have been studied. Hyper-Rayleigh scattering (HRS) has been used as a direct and accurate tool to determine effective hyperpolarizability (beta) of IPB derivatives dissolved in chloroform. Evaluation of hyperpolarizability gives an averaged values of (beta) from 140 multiplied by 10-30 to 450 multiplied by 10-30 esu. Disordering of molecular orientation for multilayer Langmuir-Blodgett films of compound C17-IPB has been studied by SHG techniques and discussed for different film thickness. It has been observed that orientation degree of the Z-type molecular str…