plotting – What I exported is different from what I drew?

enter image description here

This is the code. I wish to export figure containing vectorial elements. I successfully achieved the goal but the exported result is just subjected to distortion. How to solve this problem.

(*强度以x^2从0变到1*)
SetOptions(MaTeX, FontSize -> 30, "Preamble" -> {"\usepackage{bm}"});
a1 = DensityPlot(Abs((Sqrt(x^2 + y^2))^2), {x, -1, 1}, {y, -1, 1}, 
   ColorFunction -> GrayLevel, ColorFunctionScaling -> False, 
   RegionFunction -> (#1^2 + #2^2 <= 1 &), PlotPoints -> 300, 
   PlotTheme -> "Minimal", Background -> White, 
   PlotRange -> {{-2, 2}, {-2, 2}});
a2 = ParametricPlot(
   Table(a {Cos(t), Sin(t)}, {a, 0, 1, 0.01}), {t, 0, 2 Pi}, 
   ColorFunction -> (Hue(#3) &), 
   RegionFunction -> (#1^2 + #2^2 <= 1 &), PlotStyle -> Thick, 
   Axes -> False, Background -> Black, 
   PlotRange -> {{-2, 2}, {-2, 2}});
a3 = Rasterize((ImageMultiply(a1, a2) // ColorNegate), 
   RasterSize -> 1000);
a4 = Graphics({Dashing({0.01, 0.03}), Black, Thickness(0.015), 
    Line({{0, 0}, {0.9, 0}})}, PlotRange -> {{-2, 2}, {-2, 2}});
a5 = Graphics({PointSize(0.03), Black, Point({0.5, 0.7})});
a6 = Graphics({PointSize(0.025), Black, Point({0, 0})});
a7 = Graphics({Thickness(0.015), Black, Line({{0, 0}, {0.5, 0.7}})});
data = Table(1.2 {Cos(t), Sin(t)}, {t, 0 (Pi), 0.28 Pi, 0.05});
a8 = Graphics({Arrowheads(0.07), Black, Thickness(0.015), 
    Arrow(data)});
a9 = Graphics(Text(MaTeX("\bm{|E|^2}"), {0, 0.6}));
a10 = Show(a4, a5, a6, a7, a8, a9);
a11 = Canvas(a10, Background -> a3, FrameStyle -> False)
Export("ColorBar   " <> 
   DateString({"(Date ", "ISODate", " Time ", "Hour", "-", "Minute", 
     "-", "Second", ")"}) <> ".pdf", a11) // SystemOpen