In each system block, there should be at least two optics depending on the type of system:
More information about optic statements:
Each optic statement starts with an optic type keyword, followed by an the optic tag delimited by an @ character. If a tag is not specified, a default tag is given to the optic. The remaining lines defining the optic parameters are bracketed by { ... } braces. For example,
Mirror @ M1 {
DistanceToNext = 100
ROC = 200
}
The optic type must be one of the following keywords.
| Keyword | Description |
| BrewsterInput | Entrance face of a Brewster-angled plate. Must be linked to a BrewsterOutput optic. |
| BrewsterOutput | Exit face of a Brewster-angled plate. Must be linked to a BrewsterInput optic. |
| CrystalInput | Entrance face of a crystal. Must be linked to a CrystalOutput optic. |
| CrystalOutput | Exit face of a crystal. Must be linked to a CrystalInput optic. |
| FlatMirr | Flat mirror. Only FlatMirr and Screen optics may appear between PrismA and PrismB. If it is between prisms, must be linked to a PrismA optic. FlatMirr can also be used in place of a Mirror optic. |
| Mirror | A general mirror. |
| OutputCoupler | A special type of optic that is used at the start of out-coupled systems. |
| Screen | An information screen. A screen object is used to terminate propagation systems. If the screen is within a Brewster-angled plate, a crystal, a plate, or between prisms, it must be linked to a BrewsterInput, CrystalInput, PlateInput, or PrismA optic. |
| Source | Optic used to start propagation systems. |
| ThermalLens | A thin lens. Only a ThermalLens or a Screen object may appear between the Input and Output optics. If the thermal lens is within a Brewster-angled plate, a crystal, a plate, or between prisms, it must be linked to a BrewsterInput, CrystalInput, PlateInput, or PrismA optic, respectively. |
| ThinLens | A general thin lens. |
| PlateInput | Entrance face of a refractive plate. Must be linked to a PlateOutput optic. |
| PlateOutput | Exit face of a refractive plate. Must be linked to a PlateInput optic. |
| PrismA | First prism in a prism pair. Must be linked to a PrismB optic. |
| PrismB | Second prism in a prism pair. Must be linked to a PrismA optic. |
| Property | Description |
| DistanceToNext | Specifies the free-space distance to the subsequent optic. This property is ignored for the last optic in the system. It cannot be used for BrewsterInput, CrystalInput, PlateInput, and ThermalLens optics, or Screen when linked to an Input optic, since the spacing of these optics is governed by the Thickness property of the entrance face optic. |
| FaceAngle | The face angle of Mirror, FlatMirr, PlateInput and CrystalInput optics. See the Optics section for information about how this value is interpreted. |
| FL | The focal length of a ThinLens or ThermalLens optic. If the lens definition is astigmatic, the FL property refers to the focal length in the sagittal plane. |
| FL_tan | For astigmatic ThinLens or ThermalLens optics, the focal length in the tangential plane. |
| RefractiveIndex | Specifies the refractive index. This property is only valid for BrewsterInput, CrystalInput, PlateInput, and PrismA optics. |
| ROC | The radius of curvature of Mirror or any of the interface optics BrewsterInput, BrewsterOutput, CrystalInput, CrystalOutput, PlateInput, and PlateOutput. If the mirror or interface curvature is astigmatic, the ROC property refers to the radius of curvature in the sagittal plane. See the Optics section for information about the sign conventions in each of these. |
| ROC_tan | For astigmatic mirror or interface optics (see ROC), the radius of curvature in the tangential plane. |
| Thickness | Defines the thickness for BrewsterInput, CrystalInput, and PlateInput optics. |
Two keywords are used for linking systems and optics together. If the target of a link is missing, such as when an optic of with the tag specified by LinkedTo is not specified within the file, the linking optic is removed from the system.
| Keyword | Value | Description |
| LinkedTo | Optic tag | Links to together optics including |
| Spawn | System tag | Defines a new out-coupled system. The Spawn keyword can only be used for Mirror optics. The system block for the out-coupled system should follow after the last optic in the top-level system. |
The following flag keywords can appear anywhere within an optic statement.
| Property | Description |
| Selected | Specifies that the optic is selected. |
| LockedAngle | Specifies that the Mirror or FlatMirr optic face angle is locked, and should not be changed when optics are dragged in the Canvas. |
| Flipped | For BrewsterInput and PrismA optics, specifies that the refraction should turn the centreline anti-clockwise. If the Flipped keyword is not specified, the centreline is turned clockwise at the Brewster-angled interface. |
| Astigmatic | Specifies that the optic focal length or radius of curvature is defined separately in the sagittal and tangential planes. applies to the following optics:
|