How can I plot a Helical phase fronts similar to the following picture

Answer 1

[darova]

Use meshgrid and surf commands

[guodong zhu]

Thanks,I know the meshgrid and surf commands, but i don't know the function of the picture.

[darova]

Try

k = 1;                        % play with this
r = linspace(0,5,10);
t = linspace(0,10);
[R,T] = meshgrid(r,t);
X = R.*cos(T);
Y = R.*sin(T);
Z = k.*T;

[guodong zhu]

Thanks a lot, the code is useful. Can u give some suggestions about the functions of (c) and (d)?

[darova]

What is L?

[guodong zhu]

L is orbital angular momentum(OAM), u can refer it from https://en.wikipedia.org/wiki/Orbital_angular_momentum_of_light

If u are not a physics major, it is difficult for u to understand the OAM.

[darova]

Looks like just the same spiral copied and rotated

k = 3;                        % play with this
r = linspace(0,5,10);
t = linspace(0,5);
[R,T] = meshgrid(r,t);
X = @(T) R.*cos(T);
Y = @(T) R.*sin(T);
Z = k.*T;
cla
n = 5;
hold on
for i = 1:n
    g = surf(X(T+2*pi*i/n),Y(T+2*pi*i/n),Z);
    set(g,'FaceColor',rand(1,3),'FaceAlpha',0.5)
end
hold off
axis equal

[guodong zhu]

Thanks, Your code does work.