Open AccessKramers–Kronig relation between nonlinear absorption and refraction of C_60 and C_70
Author(s) -
C.H. Wu,
Tai-Min Liu,
Tai-Ying Wei,
Xin Li,
Yi-Ci Li,
Li-Shu Lee,
Chi Cheng Chang,
Jaw-Luen Tang,
Shanmin Yang,
TaiHuei Wei
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.022637
Subject(s) - refraction , kramers–kronig relations , absorption (acoustics) , optics , refractive index , picosecond , attenuation coefficient , nonlinear system , nonlinear optics , absorption spectroscopy , negative refraction , two photon absorption , physics , materials science , laser , quantum mechanics
Using the Z-scan technique with 532 nm 16 picosecond laser pulses, we observe reverse saturable absorption and positive nonlinear refraction of toluene solutions of both C(60) and C(70). By deducting the positive Kerr nonlinear refraction of the solvent, we notice that the solute molecules contribute to nonlinear refraction of opposite signs: positive for C(60) and negative for C(70). Attributing nonlinear absorption and refraction of both solutes to cascading one-photon excitations, we illustrate that they satisfy the Kramers-Kronig relation. Accordingly, we attest the signs and magnitudes of nonlinear refraction for both solutes at 532 nm by Kramers-Kronig transform of the corresponding nonlinear absorption spectra.