Dynamic Mechanical Analysis and Dielectric Relaxation for Second Order Nonlinear Optical Applications

1995 ◽  
Vol 392 ◽  
Author(s):  
Leah A. Sullivan ◽  
Hilary S. Lackritz
Keyword(s):  
Nonlinear Optical ◽  
Second Harmonic ◽  
Mechanical Analysis ◽  
Second Order ◽  
Mechanical Relaxation ◽  
Processing Temperature ◽  
Relaxation Techniques ◽  
Relaxation Dynamics ◽  
Dielectric Relaxations ◽  
Polymer Relaxation

AbstractRelaxation dynamics of poly(methyl methacrylate) (PMMA) and doped PMMA systems are investigated as a function of processing temperature and frequency. Polymer relaxations and changes in local mobility are responsible for chromophore reorientation and lead to a loss in second-order nonlinear optical (NLO) properties. Studying polymer relaxations enables the temporal and thermal stability of the NLO polymer systems to be more accurately and readily predicted. The polymer dynamics are studied by correlating mechanical and dielectric relaxations to polymer and chromophore relaxations that occur during chromophore reorientation in second harmonic generation experiments. Dielectric and mechanical relaxation techniques enable polymer relaxation dynamics to be observed over a broad frequency range. The plasticization effect of the NLO chromophores on the polymer relaxation dynamics is also investigated.

scholarly journals A Molecular Architectural Approach to Second-Order Nonlinear Optical Materials

1995 ◽  
Vol 392 ◽  
Author(s):  
Xiaoguang Yang ◽  
Duncan McBranch ◽  
Basil Swanson ◽  
Dequan Li
Keyword(s):  
Nonlinear Optical ◽  
Second Harmonic ◽  
Fused Silica ◽  
Second Order ◽  
Nonlinear Susceptibility ◽  
Design And Synthesis ◽  
Fundamental Wavelength ◽  
Assembled Monolayers ◽  
Methylene Groups ◽  
Nlo Chromophores

AbstractThe design and synthesis of a family of calix[4]arene-based nonlinear optical (NLO) chromophores are discussed. The calixarene chromophores are macrocyclic compounds consisting of four simple D-π-A units bridged by methylene groups. These molecules were synthesized such that four D-π-A units of the calix[4]arene were aligned along the same direction with the calixarene in a cone conformation. These nonlinear optical super-chromophores were subsequently fabricated into covalently bound self-assembled monolayers on the surfaces of fused silica and silicon. Spectroscopic second harmonic generation (SHG) measurements were carried out to determine the absolute value of the dominant element of the second-order nonlinear susceptibility, d33, and the average molecular alignment, ψ. We find a value of d33 = 60 pm/V at a fundamental wavelength of 890 nm, and ψ˜ 36° with respect to the surface normal.

ENHANCING CONVERSION EFFICIENCY IN THE SECOND-ORDER NONLINEAR OPTICAL PHENOMENA

2004 ◽  
Vol 13 (03n04) ◽  
pp. 445-449
Author(s):  
JONGBAE KIM ◽  
JUNG JIN JU ◽  
MIN-SU KIM
Keyword(s):  
Harmonic Generation ◽  
Conversion Efficiency ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Second Order ◽  
Phase Matching ◽  
Quasi Phase Matching ◽  
Optical Phenomena ◽  
Nonlinear Optical Phenomena ◽  
Second Order Nonlinearity

The distributions of electric field and the induced second-order nonlinearity are discussed in a poling scheme where the width of a periodic electrode is shorter than the conventional coherent length. The theoretical aspects of quasi-phase matching for a subsequent experiment in second harmonic generation are analyzed. The present analysis consistently explains that the conversion efficiency can be enhanced if the electrode width is shortened, and maximized if the electrode width is optimized.

Quadratic Electro-Optical Characterization of Molecular Nonlinear optical Materials

1987 ◽  
Vol 109 ◽  
Author(s):  
John C. Luong ◽  
N. F. Borrelli ◽  
A. R. Olszeuski
Keyword(s):  
Optical Materials ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Low Frequency ◽  
Second Order ◽  
Third Order ◽  
Kerr Coefficient ◽  
Molecular Compounds ◽  
Order Susceptibility

ABSTRACTA convenient method of measuring the nonlinear optical properties of molecular compounds is described. The method involves measuring the quadratic electro-optical coefficient of a polymer composite containing a variable concentration of the candidate NLO material. The X(3) (ω) value obtained by this low-frequency Kerr measurement, after local-field corrections, can be compared to the nonresonant third-order susceptibility measured by degenerate-four-wave-mixing technique on selective samples. We find that the choice of the polymer matrix dictates the contribution of second-order susceptibility to the Kerr coefficient. Therefore, our method can also be extended to the measurement of second-order susceptibility, analogous to the technique of field-induced second-harmonic-generation.

Synthesis and Second-Order Nonlinear Optical Properties of New Coumaromethacrylate-Methylmethacrylate Copolymers

1989 ◽  
Vol 173 ◽  
Author(s):  
R. A. Henry ◽  
J. M. Hoover ◽  
A. Knoesen ◽  
S. T. Kowel ◽  
G. A. Lindsay ◽  
...  
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Elevated Temperatures ◽  
Second Harmonic ◽  
Second Order ◽  
Nonlinear Optical Properties ◽  
Glass Transitions ◽  
Copolymer Films ◽  
New Family ◽  
Polymerizable Group

ABSTRACTThe synthesis and second-order nonlinear optical (NLO) properties of a new family of optically nonlinear coumarin dye-containing polymers is reported. Polymerizable coumaromethacrylate (CMA) monomers having various alkyl spacers (C2 to C5) between the polymerizable group and the chromophore were prepared and copolymerized with methylmethacrylate (MMA) and other vinyl monomers. The CMA copolymers had high chromophoric content (up to 18 × 1020) and glass transitions as high as 132°C. Spin cast films were prepared on BK7 substrates and oriented by corona-onset poling at elevated temperatures (COPET). The poled CMA copolymer films were characterized for spectroscopic absorption and second harmonic properties. A comparison of the nonlinear optical properties of poled CMA-MMA copolymers to poled guest-host systems is made. Relative to guest/host systems, CMA-MMA copolymer films exhibit larger and much more stable second-order nonlinear optical properties.

SECOND ORDER NONLINEAR OPTICAL PROPERTIES IN SILICA-BASED GLASS FILM WAVEGUIDES

1996 ◽  
Vol 05 (02) ◽  
pp. 189-204 ◽  
Author(s):  
S. HORINOUCHI ◽  
H. IMAI ◽  
H. YAMASAKI ◽  
K. FUKAO ◽  
G.J. ZHANG ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Nonlinear Optical ◽  
Glass Composition ◽  
Second Harmonic ◽  
Optical Nonlinearity ◽  
Second Order ◽  
Time Dependent ◽  
Glass Film ◽  
Second Order Nonlinearity

Phase-matched blue second harmonic generation was observed in a corona-poled Corning 7059 glass film waveguide. The induced quadratic optical nonlinearity was examined by second harmonic generation with a time dependent decay for multi-complex of SiO 2, BaO,B 2 O 3 and/or Al 2 O 3. Glass films with every possible combination of composition were fabricated and examined, The glass composition of SiO 2- BaO-B 2 O 3 and/or SiO 2- BaO-Al 2 O 3 was found to play effective roles in maintaining the induced second order nonlinearity for a longer period of time. This is supposed to be related to distributed traps which come from complex of the glass components.

scholarly journals Second Harmonic Generation in Lithiated Silicon Nanowires: Derivations and Computational Methods

2021 ◽  
Vol 3 (6) ◽  
pp. 36-46
Author(s):  
Donald C. Boone
Keyword(s):  
Second Harmonic Generation ◽  
Computational Methods ◽  
Harmonic Generation ◽  
Silicon Nanowires ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Second Order ◽  
Lithium Ions ◽  
Optical Process ◽  
Nonlinear Optical Process

This research will examine the computational methods to calculate the nonlinear optical process of second harmonic generation (SHG) that will be hypothesized to be present during lithium ion insertion into silicon nanowires. First it will be determined whether the medium in which SHG is conveyed is non-centrosymmetric or whether the medium is inversion symmetric where SHG as a part of the second-order nonlinear optical phenomenon does not exist. It will be demonstrated that the main interaction that determines SHG is multiphoton absorption on lithium ions. The quantum harmonic oscillator (QHO) is used as the background that generates coherent states for electrons and photons that transverse the length of the silicon nanowire. The matrix elements of the Hamiltonian which represents the energy of the system will be used to calculate the probability density of second-order nonlinear optical interactions which includes collectively SHG, sum-frequency generation (SFG) and difference-frequency generation (DFG). As a result, it will be seen that at varies concentrations of lithium ions (Li+) within the crystallized silicon (c-Si) matrix the second-order nonlinear optical process has probabilities substantial enough to create second harmonic generation that could possibly be used for such applications as second harmonic imaging microscopy.

First-Principles Calculations of Nonlinear Optical Response Functions in Semiconductors

1999 ◽  
Vol 579 ◽  
Author(s):  
Sergey N. Rashkeev ◽  
Walter R. L. Lambrecht
Keyword(s):  
Crystal Structure ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
First Principles ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Second Order ◽  
Response Functions ◽  
First Principles Calculations ◽  
Lmto Method

ABSTRACTWe present our implementation of the length-gauge formalism of Sipe and coworkers (Phys. Rev. B 48, 11705 (1993); ibid 52, 14636 (1995)) using the linearized muffin-tin orbital (LMTO) method and discuss its application to the calculation of second order response functions. The importance of gap corrections beyond LDA is discussed. As primary application, we discuss the second harmonic generation (SHG) coefficients of the SiC polytypes and of the chalcopyrites of both the II-IV-V2 and I-III-VI2 families. These examples illustrate the relation of the second order response function to the modification of the crystal structure and chemical substitutions.

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