Local-field effects in the second-harmonic generation from Langmuir–Blodgett monolayers

Ui, Hiroki; Tomioka, Akihiro; Nishiwaki, Takeshi; Miyano, Kenjiro

doi:10.1063/1.468367

Cited by 15 publications

(15 citation statements)

References 26 publications

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“…18,19 The effective refractive index of the SIGN system, n SIGN,eff , is roughly evaluated by fitting the reflection absorption spectra with a Lorentz function. The first and second terms represent integrals over the surface areas of the metallic substrate and gold nanosphere, respectively.…”

Section: Appendix: Shg Intensity Calculationmentioning

confidence: 99%

Second-harmonic spectroscopy of surface immobilized gold nanospheres above a gold surface supported by self-assembled monolayers

Tsuboi

Abe

Fukuba

et al. 2006

The Journal of Chemical Physics

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We have investigated linear and nonlinear optical properties of surface immobilized gold nanospheres (SIGNs) above a gold surface with a gap distance of a few nanometers. The nanogap was supported by amine or merocyanine terminated self-assembled monolayers (SAMs) of alkanethiolates. A large second-harmonic generation (SHG) was observed from the SIGN systems at localized surface plasmon resonance condition. The maximum enhancement factor of SHG intensity was found to be 3 x 10(5) for the SIGN system of nanospheres 100 nm in diameter with a gap distance of 0.8 nm. The corresponding susceptibility was estimated to be chi((2))=750 pmV (1.8 x 10(-6) esu). In the SIGN system supported with the merocyanine terminated SAMs, the SHG response was also resonant to the merocyanine in the nanogap. It was found that the SHG response of the SIGN systems is strongly frequency dependent. This leads us to conclude that the large chi((2)) is caused by enhanced electric fields at the localized surface plasmon resonance condition and is not due to an increase of the surface susceptibility following from the presence of the gold nanospheres. The observed SHG was consistent with the theoretical calculations involving Fresnel correction factors, based on the quasistatic approximation.

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Section: Appendix: Shg Intensity Calculationmentioning

confidence: 99%

Second-harmonic spectroscopy of surface immobilized gold nanospheres above a gold surface supported by self-assembled monolayers

Tsuboi

Abe

Fukuba

et al. 2006

The Journal of Chemical Physics

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“…34) In the C ∞v monolayers, the directions along the x-and the y-axes are equivalent, while that of the z-axis is singular. [35][36][37] This fact implies that the microscopic local field factor for the x-direction is equal to that for the y-direction but not that for the z-direction. The difference in the local field factor may result in the absence of the identity between the phases of the components.…”

Section: α-Quartz Crystal As a Local Oscillatormentioning

confidence: 99%

Ultrathin-film Local Oscillator for Determination of Complex Components of Second-Order Nonlinear Susceptibility

Kajikawa

Sei

Yoshida

et al. 1999

Jpn. J. Appl. Phys.

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The second-harmonic generation (SHG) interferometry technique has to date been used to determine the phase of secondharmonic (SH) light generated in a single polarization combination of a polarizer and an analyzer. However, it is not easy to compare phases of the SH light generated by a plural polarization combination, because a thick local oscillator, such as an α-quartz single crystal, has several disadvantages for this purpose. The birefringence and optical rotatory power of the quartz crystal often require further consideration on the phase relation of the SH lights with different polarizations. Thus, the full determination of the complex χ -components of an organic ultrathin film by the use of the quartz crystal is impractical. After surveying SH active systems, we found that a 2-docosylamino-5-nitropyridine (DCANP) Langmuir-Blodgett (LB) film is the most applicable for the phase measurements. A few nanometers-thick DCANP LB film, which is much thinner than the wavelength of the SH light, yields a negligible phase delay even if birefringence is present. The SHG efficiency of the film can be easily controlled by changing the number of layers. Some experimental results are addressed to demonstrate the advantage of the DCANP LB film as a local oscillator.

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“…43,44,45,46,47,48,49,50,51,81 Therefore, we shall neglect the image induced dipole term in the followed treatment.…”

Section: 89mentioning

confidence: 99%

“…26,59,60,61 There have been a few experimental and empirical theory studies on the SHG data from the interfacial monolayer, using different parameters of the macroscopic three layer model plus the microscopic local field factors. 43,44,45,46,47,48,49,50,51,62,63,64 In dealing with the macroscopic dielectric constant, generally one of the two bulk phase values were used, reducing the macroscopic problem to the same as the so-called two phase model.…”

Section: 25mentioning

confidence: 99%

“…the anisotropic two dimensional microscopic local field effect. 21,25,41,42,43,44,45,46,47,48,49,50,51,52,53 It has been well demonstrated that in majority cases the calculation of the molecular orientation is quite sensitive to the values used for these two factors. 21,25,42,51,52 In the currently accepted models of the nonlinear optics of interface, 4,34,41,53,54,55 the nonlinear radiation was treated as the result of an infinitesimally thin polarization sheet layer, and as the starting pint a macroscopic dielectric constant was assigned to this thin layer.…”

Section: Introductionmentioning

confidence: 99%

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Microscopic molecular optics theory of surface second harmonic generation and sum-frequency generation spectroscopy based on the discrete dipole lattice model

Dong¹,

Yuan²,

Liu³

et al. 2008

International Reviews in Physical Chemistry

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Two crucial issues in the interface studies with the interface specific nonlinear spectroscopy are on how to describe the macroscopic dielectric constant of the molecularly thin layer and how to calculate the anisotropic two dimensional microscopic local field effect. In the currently accepted models of the nonlinear optics, the nonlinear radiation was treated as the result of an infinitesimally thin polarization sheet layer, and a three layer model was generally employed. The direct consequence of this approach is that an apriori dielectric constant, which still does not have a clear definition, has to be assigned to this polarization layer. Because the Second Harmonic Generation (SHG) and the Sum-Frequency Generation vibrational Spectroscopy (SFG-VS) have been proven as the sensitive probes for interfaces with the submonolayer coverage, the treatment based on the more realistic discrete induced dipole model needs to be developed. Here we show that following the molecular optics theory approach the SHG, as well as the SFG-VS, radiation from the monolayer or submonolayer at an interface can be rigorously treated as the radiation from an induced dipole lattice at the interface. In this approach, the introduction of the polarization sheet is no longer necessary. Therefore, the ambiguity of the unaccounted dielectric constant of the polarization layer is no longer an issue. Moreover, the anisotropic two dimensional microscopic local field factors can be explicitly expressed with the linear polarizability tensors of the interfacial molecules. Based on the planewise dipole sum rule in the molecular monolayer, crucial experimental tests of this microscopic treatment with SHG and SFG-VS are discussed. Many puzzles in the literature of surface SHG and SFG spectroscopy studies can also be understood or resolved in this framework. This new treatment may provide a solid basis for the quantitative analysis in the surface SHG and SFG studies.

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Local-field effects in the second-harmonic generation from Langmuir–Blodgett monolayers

Cited by 15 publications

References 26 publications

Second-harmonic spectroscopy of surface immobilized gold nanospheres above a gold surface supported by self-assembled monolayers

Second-harmonic spectroscopy of surface immobilized gold nanospheres above a gold surface supported by self-assembled monolayers

Ultrathin-film Local Oscillator for Determination of Complex Components of Second-Order Nonlinear Susceptibility

Microscopic molecular optics theory of surface second harmonic generation and sum-frequency generation spectroscopy based on the discrete dipole lattice model

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