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

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.

1995 ◽  
Vol 413 ◽  
Author(s):  
Xiaoguang Yang ◽  
Laura Smilowitz ◽  
C. Thomas Buscher ◽  
Duncan McBranch ◽  
Jeanne Robinson ◽  
...  

ABSTRACTSelf-assembled molecular architechtures of nonlinear optical (NLO) chromophores and their super-chromophores are discussed. The chromophores are derivatives of azobenzene sulfonates and the super chromophores are derivatives of calix[4]stilbazole and calix[4]stilbazolium. The studies of azobenzene sulfonates are aimed at understanding the surface coverage and molecular orientation in polar self-assembled monolayers (SAMs). The optimized molecular orientation was found to be 32±3 degree and the maximum surface coverage is approximately 2–4 molecules per nm2 depending on the molecular cross-section. 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. Both simple and super-chromophores were subsequently fabricated into covalently bound selfassembled 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 = 60 pm/V at a fundamental wavelength of 890 nm. Furthermore, SHG imaging was employed to investigate the pattemed SAMs of NLO super chromophores.


1992 ◽  
Vol 247 ◽  
Author(s):  
Ru Jong Jeng ◽  
Yong Ming Chen ◽  
Braja K. Mandal ◽  
Jayant Kumar ◽  
Sukant K. Tripathy

ABSTRACTEpoxy based material incorporating 4-(4'-nitrophenylazo) phenylamine has been synthesized and subsequently functionalized with cinnamoyl groups. These materials can be easily solution-processed into thin films by spin-coating. The uncrosslinked polymer has excellent thermal and linear optical properties. Glass transition temperature of 115°C and degradation temperature (air) of 278°C were recorded.This material exhibits large second order nonlinear optical (NLO) effects subsequent to poling. In a poled film sample, second harmonic generation coefficient, d33, of 34 pm/V was observed at 1.06 μm. Crosslinking is brought about by exposure to UV radiation at 254 nm wavelength. In a poled and crosslinked film sample, a d33 of 22 pm/V was observed. This d33 value is less than the d33 value of the poled and uncrosslinked film sample due to photo-induced cis-trans isomerization and partial degradation of the NLO chromophores. Nevertheless, the poled and crosslinked film shows a much more stable second order response at ambient conditions compared to the poled film which has not been crosslinked.


2016 ◽  
Vol 45 (43) ◽  
pp. 17431-17438 ◽  
Author(s):  
D. Espa ◽  
L. Pilia ◽  
L. Marchiò ◽  
F. Artizzu ◽  
G. Di Carlo ◽  
...  

A film of [Pd(Dod2pipdt)(dmit)] incorporated into a polymethylmethacrylate matrix, showing a good second-harmonic generation, has been prepared for the first time in the class of dithione–dithiolate 2ndorder NLO-chromophores.


e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Pan Yang ◽  
Tang Xiaozhen

AbstractThe synthesis and second-order nonlinearity study of several new polyphosphazenes were described, which are composed of a new type of Yshaped nonlinear optical (NLO) chromophores attached onto polyphosphazene. They were obtained via a post-azo coupling reaction. The resulting materials were characterized by means of 1H NMR, 31P NMR, FT-IR, UV-vis, GPC and DSC. Chromophore contents up to 14 mol% have been realized. The polymers have high glass-transition temperatures, good optical transparency, and the poled film of P3- P8 revealed a resonant d33 value in the range of 11-42 pm/V by second harmonic generation (SHG) measurements.


2018 ◽  
Vol 27 (01) ◽  
pp. 1850003 ◽  
Author(s):  
Mohamadreza Soltani

Here, we propose a novel plasmonic structure, called asymmetric plasmonic nanocavity grating (APNCG), which is shown to dramatically enhance nonlinear optical process of second harmonic generation (SHG). The proposed structure consists of two different metals on both sides of lithium niobate and a thin layer of graphene. By using two different metals the nonlinear susceptibility of the waveguide would be increased noticeably causing to increase SHG. On the other hand, it consists of two identical gratings on one side. By two identical gratings, the pump beam is coupled to two opposing SPP waves, which interfere with each other and result in SPP standing wave in the region between the two gratings. The distance between two gratings will be optimized to reach the highest SHG. It will be shown that by optimizing the geometry of proposed structure and using different metals, field enhancement in APNCG waveguides can result in large enhancement of SHG.


2018 ◽  
Vol 42 (18) ◽  
pp. 15052-15060 ◽  
Author(s):  
Emine Çatal ◽  
Ergin Keleş ◽  
Nurgül Seferoğlu ◽  
Sylvain Achelle ◽  
Alberto Barsella ◽  
...  

A series of NLO chromophores based on a mono-, di- or tri-substituted triphenylamine core and allylidenemalononitrile fragments has been designed.


2008 ◽  
Vol 587-588 ◽  
pp. 268-272 ◽  
Author(s):  
M. Manuela M. Raposo ◽  
Ana M. Ferreira ◽  
Michael Belsley ◽  
E. de Matos Gomes ◽  
J.C.V.P. Moura

The synthesis of 5-arylazo- substituted bithiophenes and their UV-visible, solvatochromic and nonlinear optical properties (NLO) are described. In agreement with the solvatochromic data and also with the second-order molecular NLO characterization, the new donor-acceptor systems could find application as suitable solvatochromic probes and also as new NLO materials.


2004 ◽  
Vol 13 (03n04) ◽  
pp. 445-449
Author(s):  
JONGBAE KIM ◽  
JUNG JIN JU ◽  
MIN-SU KIM

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.


1987 ◽  
Vol 109 ◽  
Author(s):  
John C. Luong ◽  
N. F. Borrelli ◽  
A. R. Olszeuski

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.


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