TY - JOUR
T1 - Twisted π-system chromophores for all-optical switching
AU - He, Guang S.
AU - Zhu, Jing
AU - Baev, Alexander
AU - Samoć, Marek
AU - Frattarelli, David L.
AU - Watanabe, Naoki
AU - Facchetti, Antonio
AU - Ågren, Hans
AU - Marks, Tobin J.
AU - Prasad, Paras N.
PY - 2011/5/4
Y1 - 2011/5/4
N2 - Molecular chromophores with twisted π-electron systems have been shown to possess unprecedented values of the quadratic hyperpolarizability, β, with very large real parts and much smaller imaginary parts. We report here an experimental and theoretical study which shows that these twisted chromophores also possess very large values of the real part of the cubic hyperpolarizability, γ, which is responsible for nonlinear refraction. Thus, for the two-ring twisted chromophore TMC-2 at 775 nm, relatively close to one-photon resonance, n2 extrapolated to neat substance is large and positive (1.87 × 10-13 cm2/W), leading to self-focusing. Furthermore, the third-order response includes a remarkably low two-photon absorption coefficient, which means minimal nonlinear optical losses: the T factor, α2λ/n2, is 0.308. These characteristics are attributed to closely spaced singlet biradical and zwitterionic states and offer promise for applications in all-optical switching.
AB - Molecular chromophores with twisted π-electron systems have been shown to possess unprecedented values of the quadratic hyperpolarizability, β, with very large real parts and much smaller imaginary parts. We report here an experimental and theoretical study which shows that these twisted chromophores also possess very large values of the real part of the cubic hyperpolarizability, γ, which is responsible for nonlinear refraction. Thus, for the two-ring twisted chromophore TMC-2 at 775 nm, relatively close to one-photon resonance, n2 extrapolated to neat substance is large and positive (1.87 × 10-13 cm2/W), leading to self-focusing. Furthermore, the third-order response includes a remarkably low two-photon absorption coefficient, which means minimal nonlinear optical losses: the T factor, α2λ/n2, is 0.308. These characteristics are attributed to closely spaced singlet biradical and zwitterionic states and offer promise for applications in all-optical switching.
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U2 - 10.1021/ja1113112
DO - 10.1021/ja1113112
M3 - Article
C2 - 21473593
AN - SCOPUS:79955377849
VL - 133
SP - 6675
EP - 6680
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 17
ER -