added a notebook to verify the full symmetric phase masks and propagation. A comparison between ASM and FDTD is made. The comparison is ideal in the sense that phase masks are implemented assuming unitary transmission. Although not realistic in practice, it is good to compare the results obtained from the two methods. Next steps will require simulating the phase mask as a true metasurface made of nano-pillars.

metaprop_fibermode_doublet_sym.py

@@ -456,8 +456,8 @@ print("Input field integrated intensity: %.4e" % input_field_intensity)
 #make a plot and save the input field
 make_2Dplot_of(input_field_2d, choose_quantity="amplitude", save_name="input_field_amplitude", plot_zoom_x=zoom_x, plot_zoom_y=zoom_y)
 make_2Dplot_of(input_field_2d, choose_quantity="phase", save_name="input_field_phase", plot_zoom_x=zoom_x, plot_zoom_y=zoom_y)
-make_2Dplot_of(input_field_before_MS1.reshape((Nx, Ny)), choose_quantity="amplitude", save_name="input_field_before_MS1_amplitude", plot_zoom_x=full_view_x, plot_zoom_y=full_view_y)
+make_2Dplot_of(input_field_before_MS1.reshape((Nx, Ny)), choose_quantity="amplitude", save_name="input_field_before_MS1_amplitude", plot_zoom_x=zoom_x, plot_zoom_y=zoom_y)
-make_2Dplot_of(input_field_before_MS1.reshape((Nx, Ny)), choose_quantity="phase", save_name="input_field_before_MS1_phase", plot_zoom_x=full_view_x, plot_zoom_y=full_view_y)
+make_2Dplot_of(input_field_before_MS1.reshape((Nx, Ny)), choose_quantity="phase", save_name="input_field_before_MS1_phase", plot_zoom_x=zoom_x, plot_zoom_y=zoom_y)
 ###########################
 
 ###########################
@@ -468,8 +468,8 @@ target_Efield_2d = fiber_mode_pattern / np.sqrt(np.sum(np.abs(fiber_mode_pattern
 target_Efield =  target_Efield_2d.flatten() #normalized target field (intensity = 1)
 
 # Plot: Target field
-make_polarPlot_of(target_Efield_2d, choose_quantity="amplitude", save_name="target_field_1_amplitude_polar", plot_zoom_r=zoom_output_fiber_radius)
+make_2Dplot_of(target_Efield_2d, choose_quantity="amplitude", save_name="target_field_1_amplitude_polar", plot_zoom_x=zoom_x, plot_zoom_y=zoom_y)
-make_polarPlot_of(target_Efield_2d, choose_quantity="phase", save_name="target_field_1_phase_polar", plot_zoom_r=zoom_output_fiber_radius)
+make_2Dplot_of(target_Efield_2d, choose_quantity="phase", save_name="target_field_1_phase_polar", plot_zoom_x=zoom_x, plot_zoom_y=zoom_y)
 ###########################
 
 ###########################
@@ -687,7 +687,7 @@ if __name__ == "__main__":
     #save the output field for later use
     save_output_field = True
     if save_output_field:
-        np.save(f"{save_folder}/intermediate_field_0.npy", intermediate_fields[0].reshape((Nx, Ny)))
+        np.save(f"{save_folder}/intermediate_field_1.npy", intermediate_fields[0].reshape((Nx, Ny)))
         np.save(f"{save_folder}/optimized_output_field.npy", output_field.reshape((Nx, Ny)))
     # Plot results in individual PDF figures
     

metasurface/meep_fullmeta_propagation.py

@@ -35,8 +35,8 @@ unit_cell_pitch = P
 h = 0.9 #pillar height [um]
 
 #propgation distances
-d0 = 535 #[um]
+d0 = 353 #[um]
-d1 = 415 #[um]
+d1 = 218 #[um]
 d2 = d0 #[um]
 
 Nx = 1025 #pixels per dimension