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Hendry I. Elim

Publications and source records attributed to Hendry I. Elim.

8 recordsLinked to original sources
arXiv2008

Intensity-Dependent Enhancement of Saturable Absorption in PbS-Au4 Nanohybrid Composites: Evidence for Resonant Energy Transfer by Auger Recombination

Intensity-dependent enhancement of saturable absorption in a film of PbS-Au4 nanohybrid composites has been observed by femtosecond time-resolved transient absorption measurement at 780 nm. The nonlinear absorption coefficient of saturable absorption in PbS-Au4 nanohybrid composites is found to be dependent on excitation irradiance and it is determined to be -2.9 cm/GW at 78 GW/cm2, an enhancement of nearly fourfold in comparison with that of pure PbS quantum dots (QDs). The enhancement is attributed to excitation of surface plasmon by resonant energy transfer between PbS QDs and Au nanoparticles through Auger recombination.

physics.optics↗
arXiv2007

AgInSe2 Nanorods: A semiconducting material for saturable absorber

AgInSe2 nanorods (NRs) with diameter of 15 nm have been investigated for their nonlinear optical responses by using Z-scan and transient absorption techniques with femtosecond laser pulses of photon energy greater than the bandgap. At excitation irradiance of 20 GW/cm2, AgInSe2 NRs reveal saturation in the nonlinear absorption and optical Kerr nonlinearity with a recovery time determined to be a few ten picoseconds. Such large saturable absorption and Kerr nonlinearity exhibit a third-order susceptibility of 1.2 x 10-8 esu and a figure of merit of 0.04 esu.cm.s-1, making AgInSe2 NRs a promising candidate for saturable absorption devices.

nlin.SI↗
arXiv2006

Observation of Saturable and Reverse Saturable Absorption at Longitudinal Surface Plasmon Resonance in Gold Nanorods

Saturable and reverse saturable absorption at longitudinal surface plasmon resonance (SPR) in gold nanorods (Au NRs) have been observed using Z-scan and transient absorption techniques with femtosecond laser pulses. At lower excitation irradiances, the wavelength dispersion of saturable absorption has been determined near the longitudinal mode of SPR with a recovery time determined to be a few ten picoseconds on the SPR resonance. With higher excitation irradiances, reverse saturable absorption occurs and becomes dominant. The underlying mechanisms are discussed. Such reversible saturable absorption makes Au NRs an ideal candidate for optical limiting applications.

cond-mat.mtrl-sci↗
arXiv1999

New Integrable Coupled Nonlinear Schrodinger Equations

Two types of integrable coupled nonlinear Schrodinger (NLS) equations are derived by using Zakharov-Shabat (ZS) dressing method.The Lax pairs for the coupled NLS equations are also investigated using the ZS dressing method. These give new types of the integrable coupled NLS equations with certain additional terms. Then, the exact solutions of the new types are obtained. We find that the solution of these new types do not always produce a soliton solution even they are the kind of the integrable NLS equations.

solv-int↗
arXiv1999

Lax Pair Formulation and Multi-soliton Solution of the Integrable Vector Nonlinear Schrodinger Equation

The integrable vector nonlinear Schrodinger (vector NLS) equation is investigated by using Zakharov-Shabat (ZS) scheme. We get a Lax pair formulation of the vector NLS model. Multi-soliton solution of the equation is also derived by using inverse scattering method of ZS scheme. We also find that there is an elastic and inelastic collision of the bright and dark multi-solitons of the system.

solv-int↗
arXiv1999

Exact Solution of the Energy Shift in each Quantum Mechanical Energy Levels in a One Dimensional Symmetrical Linear Harmonic Oscillator

An exact solution of the energy shift in each quantum mechanical energy levels in a one dimensional symmetrical linear harmonic oscillator has been investigated. The solution we have used here is firstly derived by manipulating Schrodinger differential equation to be confluent hypergeometric differential equation. The final exact numerical results of the energy shifts are then found by calculating the final analytical solution of the confluent hypergeometric equation with the use of a software (Mathcad Plus 6.0) or a program programmed by using Turbo Pascal 7.0. We find that the results of the energy shift in our exact solution method are almost the same as that in Barton et. al. approximation method. Thus, the approximation constants (obliquity factors) appeared in Barton et. al. method can also be calculated using the results of the exact method.

quant-ph↗