AUTHORS:

Stępniewski G., Hänzi P., Filipkowski A., Janik M., Mrózek M., Stepanenko Y., Bogdanowicz R., Romano V., Heidt A., Buczyński R., Klimczak M.

ABSTRACT:

A sensitive single-beam technique for measuring both the nonlinear refractive index and nonlinear absorption coefficient for a wide variety of materials is reported. The authors 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 lambda /300 wavefront distortion is achieved in n/sub 2/ measurements of BaF/sub 2/ using picosecond frequency-doubled Nd:YAG laser pulses.

CARBON, 2023, vol. 215, art. 118465, doi: 10.1016/j.carbon.2023.118465