AbstractThe results of laser induced surface structure modifications utilizing time-resolved reflectivity measurements are presented for the pulsed laser irradiation (λ. = 1.06 μm and 0.53 μm) of thin polysilicon (poly-Si) layers of 0.1 μm, 0.45 μm and 1.0 μm in thickness on silicon substrates. It was shown that when the poly-Si layer of 0.1-0.45 thickness is totally molten, during a solidification, a large-grained structure having grain sizes exceeding the thickness of the molten Si layer is formed. At the same time, the time-resolved reflectivity changes its value nonmonotonically. This nonmonotonic behavior is due to the outcropping of growing grains onto the surface before the formation of a solid crystalline front as well as to the influence of the surface phenomena on the crystallization process.
105 W ultra-narrowband nanosecond pulsed laser at 2 μm based on monolithic Tm-doped fiber MOPA