SECOND-HARMONIC GENERATION OF FLUORESCENT PROTEINS

2013 ◽  
Vol 12 (08) ◽  
pp. 1341007
Author(s):  
JING WEI ◽  
MIN-YI ZHANG ◽  
JIN-YUN WANG ◽  
GUO-LIANG CHAI ◽  
CHEN-SHENG LIN ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Second Harmonic ◽  
Water Medium ◽  
First Order ◽  
Polarized Continuum Model

We theoretically study the second-order nonlinear optical properties of six fluorescent proteins (FPs), such as green fluorescent protein (GFP), BFP, enhanced BFP (eBFP), CFP, YFP, and DsRed. To begin with, the geometries of all these FP chromophores are optimized at B3LYP/6-311++G** level in a water medium and the polarized continuum model (PCM in water) method is adopted. Using a time-dependent density functional theory (TDDFT) method, the electronic structures and excited-state properties of chromophores are determined. Here we employ TDDFT combining with the sum-over-states (SOS) method to calculate the first-order hyperpolarizability for second-harmonic generation (SHG) optical process. Moreover, we discuss the origin of the nonlinear optical response and determine what caused the variation of first-order hyperpolarizability. Our calculations show that the charge transfers of π → π* in the central conjugated structure and p → π* charge transfers from the side chain R1 to conjugated structure of chromophores markedly affect the first-order hyperpolarizability.

scholarly journals Second Harmonic Generation, Electrooptical Pockels Effect, and Static First-Order Hyperpolarizabilities of 2,2′-Bithiophene Conformers: An HF, MP2, and DFT Theoretical Investigation

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Andrea Alparone
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Density Functional ◽  
Second Harmonic ◽  
Second Order ◽  
Pockels Effect ◽  
First Order ◽  
Hartree Fock ◽  
Electron Correlation Effects ◽  
Moller Plesset

The static and dynamic electronic (hyper)polarizabilities of the equilibrium conformations of 2,2′-bithiophene (anti-gauche and syn-gauche) were computed in the gas phase. The calculations were carried out using Hartree-Fock (HF), Møller-Plesset second-order perturbation theory (MP2), and density functional theory methods. The properties were evaluated for the second harmonic generation (SHG), and electrooptical Pockels effect (EOPE) nonlinear optical processes at the typical λ=1064 nm of the Nd:YAG laser. The anti-gauche form characterized by the S–C2–C2′–S dihedral angle of 137° (MP2/6-311G**) is the global minimum on the potential energy surface, whereas the syn-gauche rotamer (S–C2–C2′–S = 48°, MP2/6-311G**) lies ca. 0.5 kcal/mol above the anti-gauche form. The structural properties of the gauche structures are rather similar to each other. The MP2 electron correlation effects are dramatic for the first-order hyperpolarizabilities of the 2,2′-bithiophenes, decreasing the HF values by ca. a factor of three. When passing from the anti-gauche to the syn-gauche conformer, the static and frequency-dependent first-order hyperpolarizabilities increase by ca. a factor of two. Differently, the electronic polarizabilities and second-order hyperpolarizabilities of these rotamers are rather close to each other. The syn-gauche structure could be discriminated from the anti-gauche one through its much more intense SHG and EOPE signals.

scholarly journals Second Order Nonlinear Optical Properties of 4-Styrylpyridines Axially Coordinated to A4 ZnII Porphyrins: A Comparative Experimental and Theoretical Investigation

Inorganics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 45
Author(s):  
Francesca Tessore ◽  
Gabriele Di Carlo ◽  
Alessandra Forni ◽  
Stefania Righetto ◽  
Francesca Limosani ◽  
...  
Keyword(s):  
Electric Field ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Second Order ◽  
Strong Electron ◽  
Meso Position ◽  
L1 And L2

In this research, two 4-styrylpyridines carrying an acceptor –NO2 (L1) or a donor –NMe2 group (L2) were axially coordinated to A4 ZnII porphyrins displaying in 5,10,15,20 meso position aryl moieties with remarkable electron withdrawing properties (pentafluorophenyl (TFP)), and with moderate to strong electron donor properties (phenyl (TPP) < 3,5-di-tert-butylphenyl (TBP) < bis(4-tert-butylphenyl)aniline) (TNP)). The second order nonlinear optical (NLO) properties of the resulting complexes were measured in CHCl3 solution by the Electric-Field-Induced Second Harmonic generation technique, and the quadratic hyperpolarizabilities βλ were compared to the Density Functional Theory (DFT)-calculated scalar quantities β||. Our combined experimental and theoretical approach shows that different interactions are involved in the NLO response of L1- and L2-substituted A4 ZnII porphyrins, suggesting a role of backdonation-type mechanisms in the determination of the negative sign of Electric-Field-Induced Second Harmonic generation (EFISH) βλ, and a not negligible third order contribution for L1-carrying complexes.

THE INVESTIGATION OF SECOND-ORDER NONLINEAR OPTICAL PROPERTIES OF P-NITROPHENYLAZOANILINE: SECOND HARMONIC GENERATION AND AB INITIO COMPUTATIONS

2012 ◽  
Vol 11 (01) ◽  
pp. 209-221 ◽  
Author(s):  
ASLI KARAKAŞ ◽  
ZİYA ERDEM KOÇ ◽  
MICHAELA FRIDRICHOVÁ ◽  
PETR NĚMEC ◽  
JAN KROUPA
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Second Order ◽  
Photon Absorption ◽  
Nlo Properties ◽  
Hartree Fock ◽  
H Nmr

p-nitrophenylazoaniline (1) belongs to the family of compounds with conjugated bonds and delocalized π-electrons, structurally similar to the well known push-pull compound Disperse Red 1 (DR1).1 Due to the assembly of the molecule, nonlinear optical (NLO) properties are expectable and can be more or less accurately predicted. To estimate the potential for second-order NLO properties, the electric dipole moment (μ), dispersion-free dipole polarizabilities (α) and first hyperpolarizabilities (β) have been determined by density functional theory (DFT) quantum chemical calculations at B3LYP/ 6-311 + G(d, p) level. According to the computation results, the synthesized compound exhibits non-zero β values and it might have second-order NLO behavior. Title compound has been synthesized and characterized by FT-IR, 1H-NMR and UV-Vis spectroscopies. The maximum one-photon absorption (OPA) wavelengths were estimated to be shorter than 450 nm by quantum mechanical computations using the configuration interaction (CI) method. The same result was achieved by UV-Vis spectra measurements, whereas the compound exhibited good optical transparency to the visible light. Quantitative measurements of second harmonic generation (SHG) at 800 nm and 1064 nm have been performed. The relative efficiency comparable with that of KDP (kalium diphosphate) has been observed with the exciting wavelength of 1064 nm, while the other wavelength led to strong absorption of produced light by the sample. In the following more detailed study on frequency-dependent first hyperpolarizabilities using time-dependent Hartree–Fock (TDHF) method have been computed at the wavelengths used in SHG measurements.

Enhancement of second harmonic generation using a novel asymmetric metal–graphene–insulator–metal plasmonic waveguide

2018 ◽  
Vol 27 (01) ◽  
pp. 1850003 ◽  
Author(s):  
Mohamadreza Soltani
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Field Enhancement ◽  
The Other ◽  
Nonlinear Susceptibility ◽  
Optical Process ◽  
Large Enhancement ◽  
Nonlinear Optical Process

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.

scholarly journals In situ second-harmonic generation mediated photodynamic therapy by micelles co-encapsulating coordination nanoparticle and photosensitizer

RSC Advances ◽  
2017 ◽  
Vol 7 (82) ◽  
pp. 52125-52132 ◽  
Author(s):  
Xuyang Zhou ◽  
Yang Chen ◽  
Jian Su ◽  
Xiaohe Tian ◽  
Yonghuang Luo ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Property A

NIR-PDT strategy was introduced by employing a nonlinear optical conveyor bearing strong second-harmonic generation (SHG) property. A biocompatible micellic system co-delivered the conveyor and photosensitizer for in situ NIR-PDT.

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