Optical nonlinearities of iron films prepared by pulsed laser deposition

Thin films of iron were fabricated on MgO(100) substrates using pulsed laser dep osition technique. The crystalline property and surface roughness of the films w ere investigated by x-ray diffraction and atomic force microscopy, respectively . It is found that the Fe films deposited at 500 and 800℃ are of single phase, and no diffraction from randomly oriented grains or impurity phases can be obser ved. The nonlinear optical properties of continuous 9 nm-thick iron film were d etermined using the z-scan method. The results show that the ultra-thin ir on film exhibits large nonlinear refractive coefficient, n2= 709×1 0-5cm2/kW, and nonlinear absorption coefficient, β=-552×10 -3(cm/W), at the wavelength of 532 nm.