Frequency-Dependent Second-Order Hyperpolarizability of Carbon Clusters: A Semiempirical Investigation

1995 ◽  
Vol 117 (22) ◽  
pp. 6101-6108 ◽  
Author(s):  
Marianna Fanti ◽  
Giorgio Orlandi ◽  
Francesco Zerbetto
Keyword(s):  
Second Order ◽  
Carbon Clusters ◽  
Frequency Dependent

Second‐Order Instrumentation Systems with Frequency‐Dependent Stiffness and Damping

1959 ◽  
Vol 31 (11) ◽  
pp. 1457-1462 ◽  
Author(s):  
Eric Rule ◽  
Fred J. Suellentrop ◽  
Thomas A. Perls
Keyword(s):  
Second Order ◽  
Frequency Dependent ◽  
Stiffness And Damping

Frequency-Dependent Second Harmonic Generation in Acentric Chromophoric Self-Assembled NLO Materials

1994 ◽  
Vol 351 ◽  
Author(s):  
Shlomo Yitzchaik ◽  
Paul M. Lundquist ◽  
Weiping Lin ◽  
David R. Kanis ◽  
Mark A. Ratner ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Self Assembly ◽  
Second Harmonic ◽  
Second Order ◽  
Frequency Dependent ◽  
Aligned Arrays ◽  
Nlo Materials ◽  
Charge Transfer Excitation ◽  
Self Assembled

ABSTRACTAn attractive and challenging approach to the construction of robust, thin film materials with large second-order optical nonlinearities is the covalent self-assembly of aligned arrays of high-β molecular chromophores into multilayer superlattices. In this paper, we describe the dispersion of second harmonic generation (SHG) in a self-assembled (SA) monolayer containing a stilbazolium chromophore. The frequency-dependent measurements were performed on 25 Å thick monolayers on glass using a tunable (0.4–2 μm) light source based on optical parametric amplification (OPA). The SHG spectrum contains a clear two-photon resonance at hω = 1.3eV. The maximum in the second-order susceptibility coincides with a low energy chromophore-centered charge-transfer excitation at 480 nm. The experimental SHG dispersion values compare favorably with theoretical results computed using a sum-over-states (SOS) formalism. However, the measured values exhibit a somewhat broader band response than the theoretical curve, and the origin of this behavior is discussed.

Static- and frequency-dependent NLO properties of dithienothiophene and thienothiophene bridges — A computational investigation

2020 ◽  
Vol 19 (05) ◽  
pp. 2050018
Author(s):  
Sagar B. Yadav ◽  
Nagaiyan Sekar
Keyword(s):  
Density Functional ◽  
Nonlinear Optical ◽  
Chemical Reactivity ◽  
Second Order ◽  
Basis Sets ◽  
Frequency Dependent ◽  
Nlo Properties ◽  
Reactivity Descriptors ◽  
Hartree Fock ◽  
Perturbation Potential

We have explored detailed linear and nonlinear optical properties of push-pull systems bearing thienothiophene and dithienothiophene spacers. By using density functional theory (DFT), frequency-dependent strategies were applied to examine the polarizability ([Formula: see text] and hyperpolarizability ([Formula: see text] and [Formula: see text]. The set of global and range-separated hybrid functionals with different Hartree–Fock (HF) exchange percentage at two basis sets cc-pVDZ and cc-pVTZ were used to evaluate the nonlinear optical (NLO) properties. The observed trends in the absorption maxima supported by perturbation potential analysis; as the absorption maxima increases, the respective amplitude potential decreases. For the investigated compounds, [Formula: see text]-conjugation along with the type of substituted acceptor plays a crucial role in the enhancement of NLO properties. The presence of acceptor group and length of conjugation increase between the D and A group; the first- and second-order intrinsic hyperpolarizability increases, leads to enhanced first- as well as second-order hyperpolarizability. Bond length alternation (BLA)/bond order alteration (BOA) exploration suggested that compounds attain cyanine limit. The trends in NLO properties for investigated compounds are supported by chemical reactivity descriptors, hardness and hyperhardness analysis. The polarizability is linearly correlated with the hyperpolarizability parameters ([Formula: see text] and [Formula: see text] and shows a good regression coefficient by figures of merit analysis.

Transfer Function Coefficients Calculation of the High Pass Frequency-Dependent Second-Order Components Using Special Phase Frequency Response Values

2021 ◽  
Vol 105 ◽  
pp. 161-166
Author(s):  
Hanna Ukhina ◽  
Ivan Afanasyev ◽  
Valerii Sytnikov ◽  
Oleg Streltsov ◽  
Pavel Stupen
Keyword(s):  
Transfer Function ◽  
Frequency Response ◽  
Digital Filter ◽  
Second Order ◽  
Robotic Systems ◽  
Frequency Dependent ◽  
Digital Frequency ◽  
Order Components ◽  
High Pass

In this work, adjustable second-order digital frequency-dependent components that are used in robotic systems are considered. The obtained approximations of the PFR dependence on the ripple level allow us to find the digital filter transfer function denominator coefficients' values that result contributes to a more rapid rearrangement of their responses in robotic systems.

Ultrabroadband chirped pulse second-harmonic spectroscopy: measuring the frequency-dependent second-order response of different metal films

2014 ◽  
Vol 39 (18) ◽  
pp. 5293 ◽  
Author(s):  
Bernd Metzger ◽  
Lili Gui ◽  
Harald Giessen
Keyword(s):  
Second Harmonic ◽  
Metal Films ◽  
Second Order ◽  
Frequency Dependent ◽  
Chirped Pulse

Efficientab initiomethod for the calculation of frequency-dependent second-order optical response in semiconductors

1998 ◽  
Vol 57 (7) ◽  
pp. 3905-3919 ◽  
Author(s):  
Sergey N. Rashkeev ◽  
Walter R. L. Lambrecht ◽  
Benjamin Segall
Keyword(s):  
Optical Response ◽  
Second Order ◽  
Frequency Dependent
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