diff --git a/gplugins/femwell/mode_solver.py b/gplugins/femwell/mode_solver.py
index 91c3477a..ea0698db 100644
--- a/gplugins/femwell/mode_solver.py
+++ b/gplugins/femwell/mode_solver.py
@@ -95,8 +95,10 @@ def compute_component_slice_modes(
     wavelength: float = 1.55,
     num_modes: int = 4,
     order: int = 1,
-    radius: float = np.inf,
     wafer_padding: float = 2.0,
+    radius: float = np.inf,
+    metallic_boundaries: bool = False,
+    n_guess: float | None = None,
     solver: str = "scipy",
     **kwargs,
 ) -> Modes:
@@ -109,8 +111,10 @@ def compute_component_slice_modes(
         wavelength: wavelength (um).
         num_modes: number of modes to return.
         order: order of the mesh elements. 1: linear, 2: quadratic.
-        radius: bend radius of the cross-section.
         wafer_padding: padding beyond bbox to add to WAFER layers.
+        radius: bend radius of the cross-section.
+        metallic_boundaries: if True, will set the boundaries to be metallic.
+        n_guess: initial guess for the effective index.
         solver: can be slepc or scipy.
 
     Keyword Args:
@@ -160,6 +164,8 @@ def compute_component_slice_modes(
         order=order,
         radius=radius,
         solver=solver,
+        n_guess=n_guess,
+        metallic_boundaries=metallic_boundaries,
     )
 
 
@@ -167,7 +173,6 @@ def compute_component_slice_modes(
     import matplotlib.pyplot as plt
 
     start = time.time()
-
     filtered_layer_stack = LayerStack(
         layers={
             k: get_layer_stack().layers[k]
diff --git a/gplugins/gmsh/get_mesh.py b/gplugins/gmsh/get_mesh.py
index 3ceac2d2..bb5831b2 100644
--- a/gplugins/gmsh/get_mesh.py
+++ b/gplugins/gmsh/get_mesh.py
@@ -83,9 +83,9 @@ def get_mesh(
 
     # Default layer labels
     if layer_physical_map is None:
-        layer_physical_map = {}
-        for layer_name in layer_stack.layers.keys():
-            layer_physical_map[layer_name] = layer_name
+        layer_physical_map = {
+            layer_name: layer_name for layer_name in layer_stack.layers.keys()
+        }
     else:
         for layer_name in layer_stack.layers.keys():
             if layer_name not in layer_physical_map.keys():
@@ -93,23 +93,17 @@ def get_mesh(
 
     # Default meshing flags (all True)
     if layer_meshbool_map is None:
-        layer_meshbool_map = {}
-        for layer_name in layer_stack.layers.keys():
-            layer_meshbool_map[layer_name] = True
+        layer_meshbool_map = {
+            layer_name: True for layer_name in layer_stack.layers.keys()
+        }
     else:
         for layer_name in layer_stack.layers.keys():
             if layer_name not in layer_physical_map.keys():
                 layer_meshbool_map[layer_name] = True
 
-    if type == "xy":
-        if z is None:
-            raise ValueError(
-                'For xy-meshing, a z-value must be provided via the float argument "z".'
-            )
-
-        return xy_xsection_mesh(
+    if type == "3D":
+        return xyz_mesh(
             component=padded_component,
-            z=z,
             layer_stack=layer_stack,
             default_characteristic_length=default_characteristic_length,
             resolutions=new_resolutions,
@@ -136,9 +130,15 @@ def get_mesh(
             background_remeshing_file=background_remeshing_file,
             **kwargs,
         )
-    elif type == "3D":
-        return xyz_mesh(
+    elif type == "xy":
+        if z is None:
+            raise ValueError(
+                'For xy-meshing, a z-value must be provided via the float argument "z".'
+            )
+
+        return xy_xsection_mesh(
             component=padded_component,
+            z=z,
             layer_stack=layer_stack,
             default_characteristic_length=default_characteristic_length,
             resolutions=new_resolutions,
diff --git a/notebooks/femwell_01_modes.ipynb b/notebooks/femwell_01_modes.ipynb
index 19af8584..200905ba 100644
--- a/notebooks/femwell_01_modes.ipynb
+++ b/notebooks/femwell_01_modes.ipynb
@@ -61,6 +61,7 @@
     "            \"clad\",\n",
     "            \"slab90\",\n",
     "            \"box\",\n",
+    "            \"substrate\",\n",
     "        )\n",
     "    }\n",
     ")\n",
@@ -74,10 +75,10 @@
     "].thickness = 0.09  # Perturb the layer_stack before simulating\n",
     "\n",
     "resolutions = {\n",
-    "    \"core\": {\"resolution\": 0.02, \"distance\": 2},\n",
-    "    \"clad\": {\"resolution\": 0.2, \"distance\": 1},\n",
-    "    \"box\": {\"resolution\": 0.2, \"distance\": 1},\n",
-    "    \"slab90\": {\"resolution\": 0.05, \"distance\": 1},\n",
+    "    \"core\": {\"resolution\": 0.02, \"distance\": 1, \"SizeMax\": 0.2},\n",
+    "    # \"clad\": {\"resolution\": 0.2, \"distance\": 1},\n",
+    "    # \"box\": {\"resolution\": 0.2, \"distance\": 1},\n",
+    "    # \"slab90\": {\"resolution\": 0.05, \"distance\": 1},\n",
     "}"
    ]
   },
@@ -92,8 +93,9 @@
     "    cross_section=rib(width=0.6),\n",
     "    layer_stack=filtered_layer_stack,\n",
     "    wavelength=1.55,\n",
-    "    num_modes=4,\n",
+    "    num_modes=1,\n",
     "    resolutions=resolutions,\n",
+    "    n_guess=2.630929889650573,\n",
     ")"
    ]
   },
@@ -137,9 +139,19 @@
    ]
   },
   {
-   "cell_type": "markdown",
+   "cell_type": "code",
+   "execution_count": null,
    "id": "8",
    "metadata": {},
+   "outputs": [],
+   "source": [
+    "print(modes[0].n_eff)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "9",
+   "metadata": {},
    "source": [
     "## Sweep waveguide width"
    ]
@@ -147,7 +159,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "9",
+   "id": "10",
    "metadata": {
     "lines_to_next_cell": 2
    },
@@ -176,7 +188,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "10",
+   "id": "11",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -196,6 +208,23 @@
    "cell_metadata_filter": "-all",
    "main_language": "python",
    "notebook_metadata_filter": "-all"
+  },
+  "kernelspec": {
+   "display_name": "base",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.11.5"
   }
  },
  "nbformat": 4,