function plot_goldpermittivity

wp=1.37e16;  % Hz
g0=4.08e13;  % Hz
i = sqrt(-1.0);

N1=10e13;
N2=10e16;
dn = 10e12;

w=(N1:dn:N2);
wp2=wp^2;
w2 = w.*w;
epsilon = real(1.0 - wp2./(w.*(w+i*g0)));
%epsilon = 1.0 - wp2./w2;
zeroline = 0.0*w;

gcf = figure('Units','inches','Position',[.25 0.5 8 3.5],'Color',[1 1 1])
%axes('fontsize',axissize,'position',[.15 .15 .8 .73]);
hold off;
cla; % clear the screen
axis([N1 N2 -5*(max(epsilon)) 2*max(epsilon)]);
hold on;
plot(w,zeroline,'k');
plot(w,real(epsilon),'LineWidth',2);
title('Permittivity of Gold (Drude)','fontsize',20);
            xlabel('\omega [Hz]','fontsize',16);
            ylabel('\epsilon','fontsize',20);

min(epsilon)
max(epsilon)


