Dispersion of nonlinear refraction and two-photon absorption using a white-light continuum Z-scan

Dispersion of nonlinear refraction and two-photon absorption using a white-light continuum Z-scan.

We use a white-light continuum (WLC) Z-scan technique to measure the degenerate two-photon absorption spectrum and associated dispersion of the nonlinear refraction in ZnSe. The spectral components of the WLC source are separated by using a narrow band variable filter to minimize nondegenerate nonlinearities. We observe a change in sign of the ultrafast nonlinear refractive index around 0.7 of ...

Experiment and Analysis of Two-Photon Absorption Spectroscopy Using a White-Light Continuum Probe

We present an experimental technique along with the method of data analysis to give nondegenerate two-photon absorption (2PA) spectra. We use a femtosecond pump pulse and a white-light continuum (WLC) probe to rapidly generate the 2PA spectra of a variety of materials. In order to analyze data taken with this method, the spectral and temporal characteristics of the WLC must be known, along with...

Two photon absorption, nonlinear refraction, and optical limiting in semiconductors

Z-scan measurements of the anisotropy of nonlinear refraction and absorption in crystals.

The techniques most often used to determine components of the third-order susceptibility, x(3), include degenerate four-wave mixing, 1 nearly degenerate threeand four-wave mixing, 2 ellipse rotation, 3 optical third-harmonic generation,4 photoacoustics,5 beam-distortion methods,6 8 and nonlinear transmission.9 Some of these have been adapted to measure the anisotropy of x<a) .2•5•6•9 We introdu...

Determination of nonlinear absorption and refraction by single Z-scan method

We report a simplified Z-scan technique based on a study on the symmetric features of a typical Z-scan curve. The contributions from the two-photon absorption (TPA) and the nonlinear refraction (NLR) are easily separated from a closed-aperture Z-scan curve using this method. And the determination of the two nonlinearities is simplified and unambiguous. We demonstrate this method on ZnSe, CdS, a...