Cylindric lens

This element represents a “real” lens with cylindrical front and back surfaces. Furthermore, the lens consists of an optical material, which carries the refractive index model among other data. The center thickness denotes the distance of the front and back surfaces at symmetry axis of the lens.

By default, both cylinder axex are oriented along the y axis. This can be easily changed using the alignment property.

The optic shape decides which rays hit the lens (see Optic shape). Choose it so that the lens keeps a positive edge thickness: where the front and back surfaces would cross, e.g. beyond the rim of a thin biconvex lens, rays miss the rear surface.

Since this element encloses a volume of material, it can be operated as an amplifier: a pump scenario assigns it a gain model, and light travelling through the medium is amplified accordingly. Without such an assignment the lens is the passive component described here.

Analysis

• Energy Analysis

  During energy analysis, besides the common behaviour, this element does not alter the incoming the incoming light. The output is a copy of the input light. Above mentioned apertures are ignored.

• Ray tracing Analysis

  During ray tracing analysis, incoming rays are refracted on the frontsurface according to Snellius’ law of refraction. Inside the lens the ray propagate within the given medium. On the rearsurface, the rays are again refracted. A ray reaching a surface outside the optic shape misses the lens and follows the analyzer’s missed surface strategy.

• Ghost focus Analysis

  During this analysis, the lens behaves similar to the ray tracing analysis. A ray outside the optic shape passes the lens unchanged.

Ports

input_1

Input port. This represents the front surface of the lens.

output_1

Light ouput. This represents the rear surface of the lens.

Properties

front curvature

Radius of curvature of the front surface.

rear curvature

Radius if curvature of the rear surface.

center thickness

Thickness of the lens center along the optical axis.

material

The (glass-) material the lens is made of. It carries the refractive index model — a constant value or a dispersion formula such as Sellmeier or Schott — which is what the refraction at both surfaces is calculated from.

optic shape

Transversal extent of the lens: the size the material is actually available in. It decides which rays hit the lens. Defaults to a rectangle 20 mm across the curvature (x) and 30 mm along the cylinder axis (y). Both curvatures must reach the point of its edge farthest from the axis, 18 mm for the default; Open is refused.