Fluorescence Properties

The plot shown on the right shows the same model except a Bulk Scattering property has been added.

FIGURE 4.4 - Block of glass shown before (left) and after (right) Bulk

Scattering property is applied.

You can also apply importance sampling to a solid object to enhance the sampling of bulk scatter. To obtain Figure 4.5, an importance target at the base of the object increases the number of rays propagating toward the target. Each importance ray is scattered within the object.

FIGURE 4.5 - Bulk Scattering with Importance Sampling Target

Note: The flux threshold for these examples was set to 0.0005. See “Thresholds” on page 5.38.

To use bulk scattering:

1.Apply a material property appropriate for the volume within which the scattering is to be modeled.

2.Apply a Bulk Scattering property.

Fluorescence Properties Expert

Fluorescence is modeled in TracePro through a combination of fluorescence properties applied to objects and enhanced ray tracing features. Fluorescence Properties include relative absorption and relative excitation normalized to the peak molar extinction coefficient, and relative emission. Concentration of the fluorescing material can be set in the model by entering the molar concentration

TracePro 5.0 User’s Manual

4.7

Applying Properties

when applying the property to a solid object. When the model is raytraced, the raytrace is broken into two stages. In the first stage of the raytrace, rays are traced in the excitation part of the material spectrum. A by-product of the first stage of the raytrace is that TracePro source files are generated which contain rays emanating from sites in the fluorescent material. The second stage of the ray trace uses the source files to trace fluorescent rays.

FIGURE 4.6 - Fluorescence Property dialog tab.

Applying Fluorescence Properties

Database catalogs exist that contain predefined fluorescent properties. You can choose among them or you can modify or add user-defined materials by using the Fluorescence Property editor. See “Fluorescence Properties” on page 3.12.

To apply Fluorescence properties to an object in your model:

1.Select an object in your model. You can select an object by clicking it in the System Tree or in the model window.

2.Choose Define|Apply Properties and select the Fluorescence tab.

3.Select a catalog using the drop-down catalog list and select the name of the desired material using the drop-down name list.

4.Edit the Quantum Efficiency and Peak Molar Extinction values, if required

5.Enter the Molar Concentration.

4.8	TracePro 5.0 User’s Manual