Dr TIM: Ray-tracer TIM, with additional specialist scientific capabilities

Abstract

We describe several extensions to TIM, a raytracing program for ray-optics research. These include relativistic raytracing; simulation of the external appearance of Eaton lenses, Luneburg lenses and generalized focusing gradient-index lens (GGRIN) lenses, which are types of perfect imaging devices; raytracing through interfaces between spaces with different optical metrics; and refraction with generalised confocal lenslet arrays, which are particularly versatile METATOYs. Summary of revisions: added capabilities include simulation of different types of camera moving at relativistic speeds relative to the scene; visualisation of the external appearance of generalized focusing gradient-index (GGRIN) lenses, including Maxwell fisheye, Eaton and Luneburg lenses; calculation of refraction at the interface between spaces with different optical metrics; and handling of generalised confocal lenslet arrays (gCLAs), a new type of METATOY External routines/libraries: JAMA [1] (source code included) Nature of problem: visualisation of scenes that include scene objects that create wave-optically forbidden light-ray fields Solution method: ray tracing Unusual features: specifically designed to visualise wave-optically forbidden light-ray fields; can visualise ray trajectories and geometric optic transformations; can simulate photos taken with different types of camera moving at relativistic speeds, interfaces between spaces with different optical metrics, the view through METATOYs and generalised focusing gradient-index lenses; can create anaglyphs

Direct stigmatic imaging with curved surfaces

“…The virtual camera is focussed to the distance where the surface is expected to produce the image of the arrow, and indeed the image, an arrow pointing to the left which is visible close to the bottom of the sphere, can be seen sharply (while the object and the sphere are blurred). The simulation was performed with the scientific raytracer Dr TIM [15].…”

Law of refraction for generalised confocal lenslet arrays

“…Note that a generalised law of refraction for gCLAs, using the original parametrisation, had been derived previously [8]. We have also programmed the generalised law of refraction into our custom ray tracer TIM [9,10], which allows visualisation of the view through different gCLAs.…”

“…However, sometimes building highquality prototypes can be difficult and expensive. To be able to "experiment" nevertheless with many different types of METATOYs, we have written our own custom raytracer called TIM (which stands for The Interactive METATOY) [9,10].…”

“…Here we describe a parametrisation of gCLAs that is (slightly) different from that used previously, and we derive the generalised law of refraction for gCLAs parametrized in this way. We have also extended our open-source raytracer TIM [9,10] by adding the capability to trace rays through gCLAs, and we demonstrate TIM's new capability.…”

Complex imaging with ray-rotating windows

“…The real point light source lies at the apex of the cone of light rays (red cylinders) to the left of the ray-rotating window (framed with grey cylinders); the waist of the hyperboloid of light rays on the right of the window is interpreted as a complex image position. The image was calculated with scientific raytracer Dr TIM 5,6. …”