Eur.J.Phys.38(2017025209 Q Ye et al 10 Reflected 10 Figure 3. (a) The contour plot of a simulated Gaussian beam incident on plane interface at incident angle Binc 40. The planar interface locates at y=0. The cyan line at 10 A helps to display spatial separation of incident and reflected waves.(b)and(c) The green line, red line, and blue line denote, respectively, the absolute values of the plitude of E field (b) and the y component of Poynting vector(c) of the total incident and reflected waves at y 10 A denoted by the horizontal cyan line in panel (a). The complete separation in space of incident and reflected waves shows SI= Sin (SI= S)for x>0(x<0), and confirms the validity to calculate the incident and reflected power in terms of the total fields Sm=Re(E吗H1) Re(oTHres) (13) It is remarked that the implication of Sand S as energy flux density is not justified by its definition imere igure 3 shows typically the results for a beam of waist width 2Wo=4A incident on the y=0 at angle Binc= 40. The incident field E In. reflected field ere and transmitted field E are exhibited in figure 3(a). Different from a plane wave incidence, the reflected* * = = ( ) ( ) () S EH S EH 1 2 Re , 1 2 Re . 13 x x in in in re re re It is remarked that the implication of Sin and Sre as energy flux density is not justified by its definition. Figure 3 shows typically the results for a beam of waist width 2W0 = 4l incident on the interface y = 0 at angle qinc = 40. The incident field Ein, reflected field Ere and transmitted field Etr are exhibited in figure 3(a). Different from a plane wave incidence, the reflected Figure 3. (a) The contour plot of a simulated Gaussian beam incident on plane interface at incident angle qinc = 40. The planar interface locates at y = 0. The cyan line at y = 10 l helps to display spatial separation of incident and reflected waves. (b) and (c) The green line, red line, and blue line denote, respectively, the absolute values of the amplitude of E field (b) and the y component of Poynting vector (c) of the total, incident and reflected waves at y = 10 l denoted by the horizontal cyan line in panel (a). The complete separation in space of incident and reflected waves shows S1 = Sin (S1 = Sre) for x > 0 (x < 0), and confirms the validity to calculate the incident and reflected power in terms of the total fields. Eur. J. Phys. 38 (2017) 025209 Q Ye et al 7