The Detector Color object is very similar to the Detector Rect object. The main difference is that the Detector Color object stores Tristimulus data in addition to power data (and unlike the Detector Rect object, the Detector Color object does not store coherent data). Thus, the Detector Color object can be used to visualize the True Color image of a given irradiance distribution:

How to specify that the True Color image should be shown on the Detector Color object

This image can be viewed in both Position Space as well as Angle Space, so we can view the True Color image of both the irradiance and radiant intensity distributions.

A simple example in which a beam of light is used to illuminate the Detector Color object is provided in the file “Simple Example System.ZMX”. The archive (.ZAR) file for this example is located on the last page of this article. In this example, a collimated beam of light at 0.555 microns is propagated 1 mm to the Detector Color object:

Layout plot for the simple example using the Detector Color object

The color of the beam shown in the Layout plot corresponds to an RGB representation of the wavelength being traced:

How to specify that the Layout plot should color rays by wavelength

For the source, the wavelength traced is set by System Wavelengths:

How to specify that the source spectrum is defined by System Wavelengths

which are defined in the Wavelength Data dialog box:

Defining the source spectrum in the Wavelength Data dialog box

The wavelengths emitted by the source can also be determined by Tristimulus values, as described in the article “How to Model Colored and Tristimulus Sources”.

Tracing 1 million rays in this system, the following results are found for the irradiance distribution:

True Color image of irradiance distribution for simple example

The total power is given in Lumens, as expected for a True Color image (in which the photopic, i.e. human eye, response has been accounted for). We can use this same detector object to determine the amount of power on the detector in Watts, simply by switching the view to False Color (or equivalent):

How to specify False Color fo the Detector Color object

False color image of the irradiance distribution for the simple example

The total power is 1 Watt, consistent with the amount of power launched by the source. At 0.555 microns, this amount of power corresponds to 683 Lumens, as shown in the True Color image.

The radiant intensity distribution shows that all the power lands on a single pixel in angle space, as expected for a collimated beam:

True Color image of the radiant intensity distribution for the simple example

The distribution is still shown in True Color in this case, although the results may also be observed in False Color (or Grey Scale, etc.) as well. As we will see later, both Tristimulus and power values for the irradiance and radiant intensity on the detector may be obtained in the merit function using the NSDE operand.