IS THERE ANY PROBLEM IN THIS PROGRAM OF FRESNEL DIFFRACTION

Lambda=633*10^-9;
z=10*10^-3;
x=1:150;
y=1:150;
[p,q]=freqspace([1 150],’whole’);
[X Y]=meshgrid(p,q);
R=(X.^2 + Y.^2);
Z=exp(1i.*pi.*lambda.*z.*R);
mesh(Z);

PLZZZ HELP,I CANT FIND..... AND GIVE ME A SOLUTION

[Geoff Hayes]

tulika - are you saying that there is a problem, and if so, what is it? Please format your code so that it is readable. Highlight it and press the {}Code button.

[TULIKA]

Lambda=633*10^-9;
z=10*10^-3;
x=1:150;
y=1:150;
[p,q]=freqspace([1 150],’whole’);
[X Y]=meshgrid(p,q);
R=(X.^2 + Y.^2);
Z=exp(1i.*pi.*lambda.*z.*R);
mesh(Z);

it didn't give any result.and i have to code through freqspace function and i cant change this...plzz help me..

Answer 1

[Star Strider]

I was able to run your code (after correcting the quotes around 'whole' and changing lambda to Lambda in your Z assignment), but it didn’t produce the results I expected.

When I went online to troubleshoot it (the Wikipedia article on Fresnel diffraction is a good source), I also discovered Fresnel diffraction in two steps on stackoverflow. You might take a look at both to see what the problem may be with your code.

[TULIKA]

my mentor gave me a flowchart of this program and i have to code through the freqspace function.that's why....

[Image Analyst]

How did you get it to run? When I ran this:

lambda=633*10^-9;
z=10*10^-3;
x=1:150;
y=1:150;
[p, q]=freqspace([1 150], 'whole');
[X Y]=meshgrid(p,q);
R=(X.^2 + Y.^2);
Z=exp(1i.*pi.*lambda.*z.*R);
mesh(Z);

I get this:

Error using mesh (line 79)
X, Y, Z, and C cannot be complex
Error in test3 (line 9)
mesh(Z);

[Star Strider]

I erased the code I used, but I probably used hold to plot the real and imag parts, and then abs to see if that made a difference. Code ran, but the plotted results weren’t as I’d expected.

[TULIKA]

plz send me your code...i want to see the difference.and how to avoid this this problem.