Measurements of complex third-order optical susceptibility in a collinear pump–probe experiment

Abstract

We demonstrate simultaneous measurement of the real and the imaginary parts of third-order susceptibilities by use of a collinear pump-probe technique. This technique allows for good results and simple implementation. The signal analysis is based on the particular oscillatory signature versus the pump-probe delay allowed by the collinear configuration. Results are compared with interferometric measurements of a SF59 (Schott) glass sample.

Precise and absolute measurements of complex third-order optical susceptibility

“…It clearly isolates the linear mixing (linear fringes classically oscillating at the optical frequency) and the nonlinear coupling (nonlinear fringes). 7 By this technique, the measurement of the amplitude of the nonlinear fringes and the nonlinear absorption allows us to characterize the (3) tensor elements of isotropic materials.…”

“…Besides the Z-scan techniques, 1,2 spectral analysis, 3 third-harmonic generation, 4,5 and time-resolved interferometry, 6 we have recently demonstrated a new kind of collinear transient absorption experiment, 7 in which the full complex thirdorder nonlinear susceptibility can be measured.…”

Direct Observation of Ultrafast Singlet Exciton Fission in Three Dimensions

“…We build a simplified optical model of this experiment motivated by the fact that the pump-probe experiment is a measurement of photoinduced polarisation change in the third-order susceptibility χ 3 [21,22]. As the probe pulse is always temporally separated from the pump, time-ordering allows us to treat the pump-on and pumpoff probe signals as measures of the photoexcited and ground state dielectric functions (or complex refractive index) of the material, respectively.…”