Open the file "Samples > Non-sequential > Coherence > Interferometer.zmx".

This is another pure non-sequential file which demonstrates the coherence modeling capabilities of non-sequential mode.

The file models an interferometer. The rays from the rectangular source at the top left side of the layout are split by a 50/50 coating on the front surface of the Polygon Object assigned to object 2. The rays then travel down the two arms of interferometer to the detectors (objects 6 and 7) at the lower right side. The two ray paths are recombined prior to the detectors by a second Polygon Object (object 5) with a 50/50 coating. The mirror in the lower left arm of the interferometer (object 3) has an additional 0.005 degrees of tilt about the x-axis applied to it. The tilt produces unequal path lengths in the beam at the detector surfaces.

With its coherent detection capabilities, ZEMAX adds the energy in the rays that reach the detectors coherently according to the amplitude and phase of each ray detected. This allows ZEMAX to qualitatively simulate effects such as fringes in interferometers. In order to see these effects, the "Show Data" setting in the Detector Viewer settings must be set to "Coherent Irradiance" or "Coherent Phase".



Open a Detector Viewer now by clicking on the "Dvr" button in the button bar. In the settings for the Detector Viewer, set "Detector" to Detector Object 6, set "Show Data" to Coherent Irradiance and then click "OK". Observe the tilt fringes that result from the extra 0.005 degrees of tilt in the mirror (object 3).

   

Now, open the settings for the Detector Viewer, set "Show Data" to Incoherent Irradiance and click "OK". Observe that you can no longer see any fringes as we are no longer viewing the detector from a coherent perspective.

   

TIP:  In non-sequential mode, you can also see the interference from various orders of a diffraction grating. The sample file "Samples > Non-Sequential > Diffractives > Diffracting grating fringes.zmx" demonstrates this.