diff --git a/tidy3d/components/data.py b/tidy3d/components/data.py
index 690d3a16c5..6f7e84dcf0 100644
--- a/tidy3d/components/data.py
+++ b/tidy3d/components/data.py
@@ -1213,7 +1213,7 @@ def at_centers(self, field_monitor_name: str) -> xr.Dataset:
         """
 
         # get the data
-        field_monitor_data = self.monitor_data.get(field_monitor_name)
+        field_monitor_data = self[field_monitor_name]
         self.ensure_field_monitor(field_monitor_data)
 
         # get the monitor, discretize, and get center locations
@@ -1283,7 +1283,7 @@ def plot_field(
         """
 
         # get the monitor data
-        monitor_data = self.monitor_data.get(field_monitor_name)
+        monitor_data = self[field_monitor_name]
         self.ensure_field_monitor(monitor_data)
         if isinstance(monitor_data, ModeFieldData):
             if mode_index is None: