화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals, Vol.413, 2743-2752, 2004
Domain structure studies in phases of bent-shaped molecules by spatially resolved second harmonic microscopy
Several banana-shaped liquid crystalline molecules have been studied as active media for second harmonic generation (SHG) in their different thermotropic phases [1]. Besides the B(2)- and B(7)-phases, which exhibit SHG under external applied electric fields, the so-called "blue" B(4)-phase exhibits spontaneous SHG without application of any external field [2,3]. Both phases form a complex poly-domain structure which lead us to develop a SHG-Scanning microscope to perform a more detailed study of this complex systems. First experimental 2D-SHG-Scans in this molecules show the possibility to discriminate domains of different polar and NLO-properties, allowing a better understanding and analyses of this structures. A well defined polar structuring by external fields and analyses thereof is a prerequisite for the development of non-linear-optical (NLO)-applications of banana-shaped molecules like quasi-phase-matched (QPM)-waveguiding structures [4,5] or fast NLO. switches.