Advanced Materials Research Vol. 938

Abstract: In this paper we present the basic theory of nonlinear photonic crystal fibers (PCFs) with a focus on theoretical aspects of generating squeezed light using Kerr effect. The FDTD method is employed to study the guided modes of em field propagation in PCF. The degree of squeezing is determined using correlations function corresponding to the fields of light. It is shown that noise in a squeezed light is reduced to about 24% below the minimum noise observed in coherent light.

Abstract: In this paper we have reported excellent luminescence properties of novel nanophosphors synthesized through solgel method with narrow size distribution. The size and morphology of the prepared ZnO nanophosphors has been confirmed through XRD and SEM. We have investigated their photo-luminescence (PL) intensity as a function of wavelength. We have prepared ZnO nanophosphor of size 6 nm. It is observed two different emission peaks near 375 nm in the ultraviolet (UV) and near 525 nm in the visible region. The prepared ZnO nanophosphor has enough potential for optoelectronic applications. Keywords: Dosimetry; Thermo-luminescence; Zinc oxide; Nanophosphors.

Abstract: In this paper, we propose a new type of optical waveguide called silicon nanowire embedded equai-angular spiral photonic crystal fiber (SN-SPCF) using fully vectorial finite element method, where closely arranged arrays of air holes act as cladding and nanosize silicon material at the centre acts as core. We show that the proposed nanowire embedded PCF of 400 nm core diameter exhibits high anomalous group velocity dispersion (-3148 ps²/km), small third order dispersion (-8.6591 ps³/km) and high nonlinearity (443.2 W^-1m^-1) at 1550 nm wavelength. Soliton-effect pulse compression of femtosecond pulses in a silicon nanowire-spiral photonic crystal fiber at 1550 nm is numerically studied. We demonstrate a pulse compression of 75 fs input pulse to about 4 fs by the simultaneous actions of both linear effects (a large anomalous group velocity dispersion and a small third order dispersion) and the nonlinear effect (an effective high nonlinearity).

Abstract: In this article, the effect of wire-size on the effective band gap of Silicon (Si) is analyzed. The band gap is one of the most significant electronic parameters of semiconductor material. The band gap of semiconductor depends on temperature, pressure, composition, number of atoms as well as on the size of the particle. When semiconductors are synthesized at nanoscale level, their small particle size gives rise to quantum confinement and the energy bands are split into discrete levels. It is observed that effective band gap of semi-conductor depends on the size of the wire (number of atoms and dimensions) and it increases by decreasing the size of Si nanowire. The size quantization effect is noticed as a shift of the effective band gap toward lower values with increasing temperature of Si nanowire which also shows increase in atomic vibrations. Keywords: Size effect; Energy band gap; Semiconductor, effective mass; nanowire.