Hello Ambali,
To address the issues, you're encountering with plotting Surface Plasmon Polaritons (SPPs) for a multilayer system consisting of ‘InSb’ and ‘SiC’ layers separated by a vacuum gap, it seems that your MATLAB code has several key areas for improvement.
% Updated syms declaration to specify G as positive for physical solutions
syms G positive
% Updated vpasolve call with a specified range for G
solutions = vpasolve(equation, G, [0, inf]); % Limiting G to positive values
% Store the first solution if it exists
if ~isempty(solutions)
G_solutions(i) = double(solutions(1));
abs_G_solutions(i) = abs(G_solutions(i));
else
G_solutions(i) = NaN; % Assign NaN if no solution is found
abs_G_solutions(i) = NaN;
end
Explanation for the above changes:
- Positive ‘G’ Declaration: By declaring ‘G’ as positive in the symbolic variable declaration, the solver is directed to look for positive solutions, aligning with the physical expectation that the wavevector component should be real and positive for propagating modes.
- Specifying Range in ‘vpasolve’: The updated ‘vpasolve’ call includes a range [0, inf] for ‘G’. This helps the solver by providing a physical range of interest, potentially improving the accuracy and efficiency of the solution process.
- Handling No Solution Cases: The conditional check for empty solutions ‘(if ~isempty(solutions))’ ensures that the code can gracefully handle scenarios where no solution is found by the solver, assigning ‘NaN’ to the ‘G_solutions’ and ‘abs_G_solutions’ arrays for those frequencies. This prevents the code from crashing or throwing errors when solutions are not found.
Hope this helps!
