In the z scan techniques to study the nonlinear properties of nonlinear materials ,which are determined to use cw-laser or pulsing laser,?is thick or natural of the sample?
@ Dear Raad, to my mind both type of lasers are good for z-scan measurement. However to reach more precise results it"s necessary in the case cw-lasing a thickness of sample has to take less than the length of the focusing. (LF). For the pulse PS-FS lasing the spatial pulse length gets shorter than LF, while a thickness of sample can be less or bigger than LPN and that has to be taken into account. These considerations follow to approximation of given field (equal intensity).
My dear professor Eugene A. Tikhonov,
thank you very much for this reply, these answers will be in my mind in the type of this investigation
regard
Raad
hello dear Raad Shaker Alnayli . of course both CW and pulsed lasers are good for z scan but pulsed lasers are better because of thermal effect that CW lasers have on the sample and the other reason that pulsed laser is more convenient is because of its peak power that it is higher than CW lasers.
and in both cases the thickness of sample should be less than Rayleigh length of the lens.
According to my understanding if we want to look for electronic and molecular interactions and respective susceptibilities Femto sec pulsed laser is a must. With cw laser only thermo optic effects are observed. The other effects are masked by thermal effects.
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