Title

Sensitive Measurement Of Optical Nonlinearities Using A Single Beam

Abstract

We report a sensitive single-beam technique for measuring both the nonlinear refractive index and nonlinear absorption coefficient for a wide variety of materials. We describe the experimental details and present a comprehensive theoretical analysis including cases where nonlinear refraction is accompanied by nonlinear absorption. In these experiments, 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 nonlinear refraction are easily deduced from such a transmittance curve (Z-scan). Employing this technique, a sensitivity of better than λ./300 wavefront distortion is achieved in n2 measurements of BaF2 using picosecond frequency-doubled Nd:YAG laser pulses. In cases where nonlinear refraction is accompanied by nonlinear absorption, it is possible to separately evaluate the nonlinear refraction as well as the nonlinear absorption by performing a second Z scan with the aperture removed. We demonstrate this method for ZnSe at 532 nm where two-photon absorption is present and n2 is negative. © 1990 IEEE

Publication Date

1-1-1990

Publication Title

IEEE Journal of Quantum Electronics

Volume

26

Issue

4

Number of Pages

760-769

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1109/3.53394

Socpus ID

0025413944 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/0025413944

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