# How to create a specific lighting in 3D graphics for a disk?

I am trying to get a 3D disk with gradient lighting that is darker at the center and gradually goes white at the edges. I managed to get the correct lighting but could not make it a circular shape instead of a rectangle.

Graphics3D[{EdgeForm[], Opacity[0.6],
Polygon[{{-6.2, -6.2, 1.1}, {6.2, -6.2, 1.1}, {6.2, 6.2,
1.1}, {-6.2, 6.2, 1.1}},
VertexTextureCoordinates -> {{0, 0}, {1, 0}, {1, 1}, {0, 1}}]},
Lighting -> {"Spot", White}, Boxed -> False]

Clear["Global`*"];
cf[x_] := Blend[{Red, White}, x];
RegionPlot3D[x^2 + y^2 <= 1 && -0.02 < z < 0.02
, {x, -1, 1}, {y, -1, 1}, {z, -1, 1}
, Mesh -> {0, 0, 1}
, MeshStyle -> Directive @@ {Thick, Lighter@Pink}
, ColorFunction -> Function[{x, y, z}, cf[(x^2 + y^2)^(1/5)]]
, ColorFunctionScaling -> False
, MaxRecursion -> 4
, PlotPoints -> 80
, Lighting -> {"Spot", White}
, Boxed -> False
, Axes -> False
, SphericalRegion -> True
]

Notes

1. Actual on-screen resolution is better than shown in the gif file above.

2. The ring at the boundary can be removed by commenting out the Mesh commands.

3. More PlotPoints are required to display thinner disks properly.

• How to record the animation of turning the plot object to gif?@Syed Jan 28 at 5:58
• I use ScreenToGif. @metroidman
– Syed
Jan 28 at 6:08
ParametricPlot3D[
{u Sin[Pi/2] Cos[v], u Sin[Pi/2] Sin[v], u Cos[Pi/2]}, {u, 0, 1}, {v, 0, 2 Pi},
Axes -> False,
Boxed -> False,
Lighting -> AmbientLight[White],
Mesh -> None,
PlotPoints -> 60,
PlotRange -> {{-1, 1}, {-1, 1}, {-1, 1}},
TextureCoordinateFunction -> ({#1, #2} &),