Coma influence Figure 4 is the simulation result of coma effect for
the structured laser beam as coefficient A c which is Selumetinib molecular weight assigned with different values. The intensity distribution of the donut-shaped laser spot on the xy plane is revealed in Figure 4a, b, c; corresponding coefficient A c values are 0.5, 0.25 and 0.1, respectively. Figure 4d, e, f stands for the calculated simulations of optical intensity on the yz plane with A c values equal to 0.5, 0.25 and 0.1 in sequence. Figure 4g, h, i shows the corresponding cross-sectional profiles of light intensity distribution on the y axis as A c is 0.5, 0.25 and 0.1, respectively. These figures in Figure 4 clearly illustrate the gradual transformation of light distribution induced by coma effect. The dark core of the donut-shaped pattern is stretched along one direction with the increase of A c . Meanwhile, GDC-0449 manufacturer light intensity changes and becomes a monosymmetric distribution. It can be clearly observed that the dark spot at the core of the laser beam turns into an elliptical shape as A c increases. Figure 4 Simulation result of coma effect. The simulated donut-shaped focal spot intensity vs coma effect on the xy plane: (a) A c = 0.5, (b) A c = 0.25 and (c) A c = 0.1. The corresponding intensity on the yz plane: (d) A c = 0.5, (e) A c = 0.25, and (f) A c = 0.1. Intensity
along the y axis: (g) A c = 0.5, (h) A c = 0.25, and (i) A c = 0.1. It makes sense to compare the results of the experiments Rebamipide and simulations. Their resemblances are easily found out. First, the calculated results shown in Figure 4a, b, c have similar patterns with those experimental patterns imaged in Figure 4a, b, c, respectively. The donut-shaped focal spot is a semilunar appearance in both experiment and simulation. Next, the gradual transformation of nanopillars in the experiment has the same variation tendency with the dark spots in the numerical simulation. Figure 4d, e, f illustrates the asymmetric intensity distribution on the yz plane; they explain the reasons why the two sides of the nanopillars are ruptured with different depths. Furthermore, Figure 4g, h, i has
shown that the depletion of light intensity increased with the increased A c , which correctly reflects the variation of depths at the two sides of the nanopillars in Figure 4d, e, f. Thus, coma effect is the main influence factor which results in nonideal nanopillar patterns in Figures 2 and 3. It should be noted that because of the conical shape of AFM probe tip, the height of the nanopillars is not exactly available with AFM observation. However, the spatial characters of the donut-shaped focal spot can be correctly reflected, and the height of the nanopillar can be relatively revealed. Figure 5 is the simulation about the donut-shaped laser distributing on the focal plane and the axial plane. It indicates that the height of the nanopillar can be as large as one λ or more.