| Step | Action |
| 1 | From the Draw menu, select Observation Vertical Line. |
| 2 | Place the Observation Line in the desired position in the layout. |
| 3 | Double-click the observation line. The Observation Properties — Vertical Line dialog box appears. |
| 4 | On the General tab: In Center, Offset, type/select the following:
Horizontal: 0.5 Vertical: 0.0 X Length Offset: 3.0 Label: ObservationLine1 Note: Observation line 1 will detect the reflection spectrum |
| 5 | Repeat above step1-4 to design another Observation line to detect the transmission spectrum.
Horizontal Expression: 2+36*cell_length+1 Horizontal Offset: 0.0 Vertical Offset: 0.0 X length Offset: 3.0 Label: ObservationLine2 |
Note: As an optional choice, we can also set an observation point after the grating. This observation point will record the time domain response. It allows us to check if the response is convergent or not.