this program didn't give proper output due to value...plzzz check

        * *In this case, D1 = 10 m, D2 = 50microm,sigmad= 0.25 mm;lamc=15*10^-4;lamd=10*10^-4;* *
        now the program didn't give output
        x=1:150;y=1:150;
        [p,q]=meshgrid(x,y);
        lamc=15*10^-4;
        lamd=10*10^-4;
        d2=100*10^-6;
        d1=10;
        sigmad=2.5*10^-6;
        a=exp((j*pi/(lamc*d2)).*(p^2-q^2));
        imshow(a,[]);  
        b= sinc((pi/2*lamd*d2)*(p^2-q^2));
         imshow(b,[]);
        c=exp(-2*((pi*sigmad/(lamc*d1))*(p-q))^2);
        imshow(c,[]);
        f=a*b*c;
        imshow(f,[])
    * * *input variable should be like above measurement,but dont give output for that any value* * *