We present a review of experimental data on the nonlinear optical properties of thermotropic and lyotropic liquid crystals probed by the Z-scan technique. Depending on the time scale, different processes originate a nonlinear optical response. Particularly, at nanosecond range, the physical processes associated with the nonlinear response in thermotropics are not completely understood. In lyotr...

Organic push–pull chromophoric system containing thiazole Schiff bases were synthesized from aminothiazole intermediate. These novel chromophores possessed excellent thermal and optical properties with complete transparency in the visible spectral region. Thermogravimetric analysis revealed that all dyes were thermally stable at temperatures above 300 C. The third-order nonlinear optical studie...

We report our results on nonlinear optical properties of 2(3), 9(10), 16(17), 23(24) tetra tert-butyl phthalocyanine and 2(3), 9(10), 16(17), 23(24) tetra tert-butyl Zinc phthalocyanine studied using Z-scan technique with 800 nm femtosecond and 532 nm nanosecond pulses. Nonlinear absorption behavior in both femtosecond and nanosecond domains was studied in detail. We observed three-photon absor...

We present a technique in which small solute nonlinearities may be extracted from large solvent signals by performing simultaneous Z-scans on two samples (solvent and solution). By using a dual-arm Z-scan apparatus with identical arms, fitting error in determining the solute nonlinearity is reduced because the irradiance fluctuations are correlated for both the solvent and solution measurements...

We demonstrate a new Z-scan measurement technique that permits the use of non-Gaussian beams and thick, as well as thin, samples. We expect that this technique will make possible the measurement of optical nonlinearities by the use of lasers that previously would have been unsuitable for this purpose, because of either inadequate beam quality or inadequate power. Another advantage of this techn...

We describe a sensitive technique for measuring nonlinear refraction in a variety of materials that offers simplicity, sensitivity and speed. The transmittance of a sample is measured through a finite aperture in the far -field as the sample is moved along the propagation path (z) of a focused Gaussian beam. The sign and magnitude of the nonlinearity is easily deduced from such a transmittance ...

We present an experimental study of Z-scan measurements of the nonlinear response of cold Cs atoms in a magneto-optical trap. Numerical simulations of the Z-scan signal accounting for the nonuniform atomic density agree with experimental results at large probe beam detunings. At small probe detunings a spatially varying radiation force modifies the Z-scan signal. We also show that the measured ...

By treating laser-induced optical Kerr nonlinearity as a noninstantaneous decaying process, we present the pulse-duration-dependent Z-scan analytical expressions for an arbitrary aperture and an arbitrary nonlinear magnitude. This theory has the capacity to characterize the third-order nonlinear refraction induced by a laser pulse with its temporal duration being much longer than or comparable ...