| Description |
Optical and nonlinear optical properties of single crystal InS are studied in detail. InS single crystals are grown by flux method at TIFR and they showed low transmission in 200-2500 nm wavelength and exhibited direct band gap of 2.09 eV. Nonlinear optical response is investigated by Z-scan technique using a femtosecond laser of 800 nm wavelength. At excitation intensity of 0.32 GW/cm2, the absorption coefficient was estimated to be whereas the nonlinear refractive index was calculated to be
Magnetic fluids, in the presence of external magnetic fields, forms magnetic chains or columns which in turn manifest into interesting phenomenon like modulation of light transmission. The light transmission through Fe3O4 magnetic fluid is investigated and a decrease in transmission has been observed in the wavelength range of 400-750 nm (stop gap). Furthermore, the gap deepens with increase in magnetic field. It has been observed that the luminescence of CdTe quantum dots and that of Alexa Fluor 405 dye in Fe3O4 magnetic fluids get altered significantly. In magnetic fluid medium, the emission of CdTe quantum dots at ~650 nm enhances whereas the emission of Alexa Fluor 405 dye at ~410 nm gets suppressed. These observations are the manifestation of stop gap formation (400-750 nm) in Fe3O4 fluid in presence of applied magnetic field.
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