S. Chandrasekhar

Bio: S. Chandrasekhar is an academic researcher from Raman Research Institute. The author has contributed to research in topics: Liquid crystal & Biaxial nematic. The author has an hindex of 31, co-authored 124 publications receiving 3368 citations. Previous affiliations of S. Chandrasekhar include Royal Institution & University of Mysore.

Influence of Bond-Orientational Order on the Switching Time of Ferroelectric Smectics

Abstract: We report studies of the bulk switching time as a function of temperature in the chiral smectic C (C*) and chiral smectic I (I*) phases of 4-(2-methylbutyl) phenyl 4′-(octyloxy)-(1,1′)-biphenyl-4-carboxylate (8OSI*) which shows a continuous evolution from the fluid C* to the hexatic I* phase. The thermal variation of the switching time is found (to our knowledge for the first time) to scale remarkably well with the hexatic order parameter for the two phases determined experimentally by Brock et al1 for 8OSI, the racemic form of 8OSI*. Similar correlation is observed in the case of 8SI*, the alkyl analog of 8OSI*, which shows a first order C*-I* transition.

The optical rotatory dispersion of quartz

Abstract: Many formulae have been proposed to express numerically the rapid increase of the rotatory power of quartz with decrease of wavelength. An examination of these formulae shows that they are wholly inappropriate for the case of quartz. It has been shown that the entire range of data from the visible to the extreme ultraviolet is accurately represented by a new type of formula involving only two constants,viz., $$\rho = \frac{{k\lambda ^2 }}{{(\lambda ^2 - \lambda _0 ^2 )^2 }},$$ wherek=7·19 and γ0 = 0·0926283μ. A theoretical interpretation of the new formula has been given on the basis of a simple coupled oscillator model.

On the Propagation of Light Through Thin Cholesteric and Twisted Nematic Films

Abstract: The theory of light propagation through very thin cholesteric and twisted nematic films is discussed.

Handbook of Optical Materials

Abstract: CRYSTALLINE MATERIALS Introduction Physical Properties Optical Properties Mechanical Properties Thermal Properties Magnetooptic Properties Electrooptic Properties Elastooptic Properties Nonlinear Optical Properties GLASSES Introduction Commercial Optical Glasses Specialty Optical Glasses Fused Silica Fluoride Glasses Chalcogenide Glasses Magnetooptic Properties Electrooptic Properties Elastooptic Properties Nonlinear Optical Properties Special Glasses POLYMERIC MATERIALS Optical Plastics Index of Refraction Nonlinear Optical Properties Thermal Properties Engineering Data METALS Physical Properties of Selected Metals Optical Properties Mechanical Properties Thermal Properties Mirror Substrate Materials LIQUIDS Introduction Water Physical Properties of Selected Liquids Index of Refraction Nonlinear Optical Properties Magnetooptic Properties Commercial Optical Liquids GASES Introduction Physical Properties of Selected Gases Index of Refraction Nonlinear Optical Properties Magnetooptic Properties Atomic Resonance Filters APPENDICES Safe Handling of Optical Materials Abbreviations, Acronyms, and Mineralogical or Common Names for Optical Materials Abbreviations for Methods of Preparing Optical Materials and Thin Films Fundamental Physical Constants Units and Conversion Factors

Dendron-Mediated Self-Assembly, Disassembly, and Self-Organization of Complex Systems

Abstract: Dendron-mediated self-assembly, disassembly, and self-organization of complex systems have been investigated. The most ideal building blocks would need to display shape persistence in solution and in the solid state, since only this feature provides access to the use of complementary methods of structural analysis. Most supramolecular dendrimers are chiral even when they are constructed from nonchiral building blocks and are equipped with mechanisms that amplify chirality. This poses additional challenges associated with the understanding of the structural origin of chirality in different supramolecular structures through combinations of structural analysis methods. While many supramolecular structures assembled from dendrimers and dendrons resemble some of the related morphologies generated from block-copolymers, they are much more complex and are not determined by the volume ratio between the dissimilar parts of the molecule.

Discotic Liquid Crystals: From Tailor-Made Synthesis to Plastic Electronics

Abstract: Most associate liquid crystals with their everyday use in laptop computers, mobile phones, digital cameras, and other electronic devices. However, in contrast to their rodlike (calamitic) counterparts, first described in 1907 by Vorlander, disklike (discotic, columnar) liquid crystals, which were discovered in 1977 by Chandrasekhar et al., offer further applications as a result of their orientation in the columnar mesophase, making them ideal candidates for molecular wires in various optical and electronic devices such as photocopiers, laser printers, photovoltaic cells, light-emitting diodes, field-effect transistors, and holographic data storage. Beginning with an overview of the various mesophases and characterization methods, this Review will focus on the major classes of columnar mesogens rather than presenting a library of columnar liquid crystals. Emphasis will be given to efficient synthetic procedures, and relevant mesomorphic and physical properties. Finally, some applications and perspectives in materials science and molecular electronics will be discussed.