Christian Bosshard, Rolf Spreiter, and Peter Günter, "Microscopic nonlinearities of two-component organic crystals," J. Opt. Soc. Am. B 18, 1620-1626 (2001)
We determine the molecular first-order hyperpolarizability β of the highly nonlinear organic salt 4-N,N-dimethylamino-4′-N′-methyl stilbazolium tosylate (DAST, at λ = 1542 nm) and the cocrystal 4-{2-[1-(2-hydroxyethyl)-4-pyridylidene]-ethylidene}-cyclo-hexa-2,5-dien-1-one)–(methyl 2,4-dihydroxybenzoate) (M2-MDB, at λ = 1907 nm) in solution. These values are compared with the molecular first-order hyperpolarizabilities in the solid state, calculated with the measured nonlinear optical coefficient of the crystals. For both materials we show that the molecular nonlinearity in the solid state is considerably smaller than in solution. This lowering of the nonlinearity is attributed to the relatively strong Coulomb interactions in DAST and to the very strong hydrogen bonding in M2-MDB.
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Measured First-Order Hyperpolarizabilities of the Merocyanine Dyes at λ = 1907 nm and DAST at λ = 1542 nma
Material
[nm]
μ
Cm]
at
at λ = ∞
M1 (methanol)
480
3.8
M2 (methanol)
485
3.6
M2-MDB (methanol)
490
6.3
M2-MDB (DMSO)
576
6.3
2.6
2.2
DAST (DMSO)
471
–
–
1.3
2.2
The values for the dipole moments are calculated values based on the finite-field method with the AM1 parametrization.
is given for the experimental wavelength and calculated for infinite wavelengths with the two-level model
at λ = 1542 nm based on
at λ = 1907 nm measured in dioxane).
is the wavelength corresponding to the main electronic transition. It should be noted that we assumed in first approximation that
Table 2
Calculated First-Order Hyperpolarizabilities
and Absolute Values of the Experimental First-Order Hyperpolarizabilities Extrapolated to Infinite Wavelengths and Multiplied by 6/5 to Convert to the Calculated Values [see Eq. (8)]
Material
M2
201
2500
M2, protonated
151
–
MDB
1.4
–
M2-MDB
293
870 (methanol)
Stilbazolium
201
880
Tosylate
8.4
–
Table 3
Measured Nonlinear Optical Coefficients
(at λ = 1542 nm) and Wavelength of Maximum Absorption of DAST and M2-MDB (Phases I and II) in the Solid State Derived from the Dispersion of the Refractive Indicesa
Material
[nm]
[pm/V]
[pm/V]
DAST
535
290 ± 15
1530 ± 100
M2-MDB phase I
474
78 ± 10
980 ± 130
M2-MDB phase II
540
107 ± 10
2140 ± 200
Also given are the nonlinear optical coefficients
estimated from measured first-order hyperpolarizability
by use of the diluted gas model.
Table 4
Comparison of the First-Order Hyperpolarizabilities of DAST and M2-MDB in Solution and in the Solid Statea
The measured values are indicated by (*), the values at other wavelengths are calculated from the measured ones by use of the two-level model to take into account dispersion. The value at λ = ∞ was extrapolated to infinite wavelengths (= static value), also by use of the two-level model. It should be noted that we assumed in first approximation that
which, however, does not influence the main conclusion drawn from this study.
Tables (4)
Table 1
Measured First-Order Hyperpolarizabilities of the Merocyanine Dyes at λ = 1907 nm and DAST at λ = 1542 nma
Material
[nm]
μ
Cm]
at
at λ = ∞
M1 (methanol)
480
3.8
M2 (methanol)
485
3.6
M2-MDB (methanol)
490
6.3
M2-MDB (DMSO)
576
6.3
2.6
2.2
DAST (DMSO)
471
–
–
1.3
2.2
The values for the dipole moments are calculated values based on the finite-field method with the AM1 parametrization.
is given for the experimental wavelength and calculated for infinite wavelengths with the two-level model
at λ = 1542 nm based on
at λ = 1907 nm measured in dioxane).
is the wavelength corresponding to the main electronic transition. It should be noted that we assumed in first approximation that
Table 2
Calculated First-Order Hyperpolarizabilities
and Absolute Values of the Experimental First-Order Hyperpolarizabilities Extrapolated to Infinite Wavelengths and Multiplied by 6/5 to Convert to the Calculated Values [see Eq. (8)]
Material
M2
201
2500
M2, protonated
151
–
MDB
1.4
–
M2-MDB
293
870 (methanol)
Stilbazolium
201
880
Tosylate
8.4
–
Table 3
Measured Nonlinear Optical Coefficients
(at λ = 1542 nm) and Wavelength of Maximum Absorption of DAST and M2-MDB (Phases I and II) in the Solid State Derived from the Dispersion of the Refractive Indicesa
Material
[nm]
[pm/V]
[pm/V]
DAST
535
290 ± 15
1530 ± 100
M2-MDB phase I
474
78 ± 10
980 ± 130
M2-MDB phase II
540
107 ± 10
2140 ± 200
Also given are the nonlinear optical coefficients
estimated from measured first-order hyperpolarizability
by use of the diluted gas model.
Table 4
Comparison of the First-Order Hyperpolarizabilities of DAST and M2-MDB in Solution and in the Solid Statea
The measured values are indicated by (*), the values at other wavelengths are calculated from the measured ones by use of the two-level model to take into account dispersion. The value at λ = ∞ was extrapolated to infinite wavelengths (= static value), also by use of the two-level model. It should be noted that we assumed in first approximation that
which, however, does not influence the main conclusion drawn from this study.