Z-Scan
The Z-scan experimental technique is used for measuring the nonlinear refractive index and nonlinear absorption coefficient of optical materials.
The sample is translated along an optical path of a focused laser beam and its intensity is simultaneously measured with open-aperture and closed-aperture photodiodes. When the sample is in the vicinity of beam focus, changes in the closed-aperture signal are mainly caused by nonlinear refraction-induced self-focusing, while the open-aperture signal deviation is mostly due to nonlinear absorption. Simultaneous fitting of the measured Z-scan traces with the theory allows for the identification of both refraction and absorption nonlinear parameters of the material.
The Z-scan measurement can be carried out inside the HARPIA-TB module using the harmonics of PHAROS or CARBIDE laser fundamental radiation or optical parametric amplifier (OPA) pump pulses. In the latter case, dispersion of nonlinear parameters can be measured, as well.
