Third-order polarizabilities of long-chain molecules

Hermann, J. P.; Ducuing, J.

doi:10.1063/1.1663197

Cited by 230 publications

(59 citation statements)

References 6 publications

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“…It describes the nonlinearity per molecule and is given by [26] " ( (Other definitions of y (3) without factor 24 and £ 0 are sometimes used [1,34,36].) The hyperpolarizability values y (3) are listed in Table 1 (1 Cm 4 /V 3 = 8.0888 x 10 24 esu).…”

Section: Resultsmentioning

confidence: 99%

Measurement of third-order nonlinear susceptibilities by non-phase matched third-harmonic generation

Thalhammer

Penzkofer

1983

Appl. Phys. B

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liquids, solids and air are determined by third-harmonic generation. The samples are placed behind the focal region of a laser beam in an evacuated environment to avoid third-harmonic generation of the surroundings. For fluid media the sample cell is made out of two thin fused quartz plates and oriented to an angle of zero net third-harmonic production in each window (minimum Maker fringe position). PACS: 42.65The measurement of third-order nonlinear susceptibilities x (3) ( -co 3 ; co v co v coJ responsible for thirdharmonic generation is aggravated by disturbing light production in surrounding media (sample cell, air). Avoiding the influence of the surrounding substances in the light path by tight focussing (sample length longer than confocal parameter) results in zero thirdharmonic generation under phase-matched condition and for positive phase-mismatch Ak = k 3 -3k x >0 (normal dispersive media). Only in anomalous dispersive matter light generation at frequency co 3 occurs [1,2]. In a collimated pump beam (frequency coj the third-harmonic light is periodically generated and annihilated for Ak + 0 and efficient light generation requires Ak = 0. Circularly polarized laser light does not generate third-harmonic light in transparent media at all [6].Third-order nonlinear susceptibility values # (3) ( -co 3 ; co v co 1 ,co 1 )of gases were obtained by putting a gas cell with its entrance window (absorbing at co 3 ) in the focal plane of a laser [1], The susceptibilities of some solids were measured in reflection [3]. A comparison of third-harmonic generation with cascading secondorder processes was used to derive x In this paper we report on an accurate method to determine the third-order nonlinear susceptibilities X (3) ( -co 3 ; co v co v co t ) of solids, liquids and gases. Third-harmonic generation in a slightly diverging beam (thin sample behind focal plane of a lens) is studied. Third-harmonic generation in air along the path of the laser beam is avoided by putting the sample into a vacuum chamber. The entrance and exit windows of the sample cell for liquids and gases are made out of thin plane fused silica plates (thickness: «0.2 mm). By tilting the cell to a Maker fringe minimum position for each window [11] no thirdharmonic light is produced in each of the windows. The cell is slightly wedged in order to record a Maker fringe curve when the filled cell is laterally shifted relative to the light path.

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Section: Resultsmentioning

confidence: 99%

Measurement of third-order nonlinear susceptibilities by non-phase matched third-harmonic generation

Thalhammer

Penzkofer

1983

Appl. Phys. B

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“…Equation (15) gives a reasonable result. An enlargement of yg } due to conjugated double bonds was discussed in [18][19][20][21]. Here we need the conjugated double bonds only to bring the S x absorption band to the visible region between co 1 and co 3 .…”

Section: Discussionmentioning

confidence: 99%

Third-order nonlinear susceptibilities of dye solutions determined by third-harmonic generation

Leupacher

Penzkofer

1985

Appl. Phys. B

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Abstract. The third-order nonlinear susceptibilities x { xxxx ( -^ w i> w i> &>i) versus concentration are determined for rhodamine 6G, fuchsin, and methylene blue in methanol. Third-harmonic generation of a modelocked Nd-glass laser is applied. The real and imaginary part of the nonlinear susceptibility are measured. A resonance enhancement due to absorption bands is observed. Here we determine the dependence of third-order nonlinear susceptibilities xx 3 xxx ( -^3; co l9 co u co x ) on dye concentration for rhodamine 6G, fuchsin and methylene blue in methanol. The efficiency of conversion of picosecond light pulses of a mode-locked Ndglass laser to the third harmonic is measured. The nonlinear susceptibilities are deduced by comparison with calculations [7]. The absorption coefficients and refractive indices entering the calculations are separately measured [8,9]. The nonlinear susceptibilities comprise contributions from the solvent and the solute. The complex solute hyperpolarizabilities are determined and compared with the real solvent hyperpolarizability. The resonance enhancement is analyzed.

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“…Because of the desire for higher-order nonlinearity, say third harmonic generation [7], recent efforts have been focused on organic materials or polymers, in particular, on those equipped with appropriately constituted or substituted conjugation. These systems may be the suitable candidates for developing highly enhanced electronic nonlinear optical polarization responses [8,9]. It is believed that the large electron delocalization is responsible for large values of the nonlinear optical coefficients and this can be met with the T electrons in conjugated molecules and polymers where charge asymmetry can also be adequately introduced to obtain noncentrosymmetric structures.…”

Section: Introductionmentioning

confidence: 98%

Semiempirical calculations of molecular polarizabilities and hyperpolarizabilities of polycyclic aromatic compounds

Lee

1992

Int J of Quantum Chemistry

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The correlation of 2D conjugation and the nonlinear properties of a series of polycyclic aromatic compounds were studied by performing semiempirical calculations using the MOPAC package. For linear polyacenes, both linear and nonlinear properties are found to be increased as the number of six-membered rings increases. In general, the polarizabilities, (a), and second hyperpolarizabilities, (y), are found to correlate very well with total resonance energies. In the case of first hyperpolarizabilities, (p), symmetry is the dominating factor. 0 1992 John Wiley & Sons, Inc.

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Third-order polarizabilities of long-chain molecules

Cited by 230 publications

References 6 publications

Measurement of third-order nonlinear susceptibilities by non-phase matched third-harmonic generation

Measurement of third-order nonlinear susceptibilities by non-phase matched third-harmonic generation

Third-order nonlinear susceptibilities of dye solutions determined by third-harmonic generation

Semiempirical calculations of molecular polarizabilities and hyperpolarizabilities of polycyclic aromatic compounds

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