Fig 1.
Demonstration of light confinement offered by the conical geometry.
The sketch of simulated geometries (a). Total enclosed power with respect to polar angle graph obtained from OpticStudio simulations (b). Supplied power to the LIDs is set to 1 Watt.
Fig 2.
Design and adjustable field performance of the EUCLID.
3D model of EUCLID, adjustable rod positioned at 0mm (a) and 15mm (b). Simulation of output radiance profiles (c), the cross section (d) and heatmaps (e) of intensity images of the sample acquired from the setup given in S1 Fig for different rod positions. Rod positioned at 0mm corresponds to nominally flat base surface of the cone. The scale bar is 500μm.
Fig 3.
Power coupling simulation results.
Total enclosed power with respect to polar angle graph calculated by Non-sequential ray tracing simulations. Full output characteristic of various conical LIDs (a). Zoomed sections of the left figure (b), (c), (d), (e). Best performing conical LID is indicated with the bold lines. The acceptance angles for the lenses are 32.29°, 22.28°, 17.66° and 10.70° for lens 1, 2, 3 and 4, respectively.
Table 1.
Light coupling performances of LIDs.
Fig 4.
Uniformity regions of different illumination sources.
The red and green circles indicate the area where the irradiance profile deviation is < 1% and < 0.5%, respectively. The uniform irradiance circles are shown for: direct LEDs (a), spherical LID (b), EUCLID (d) in Koehler alignment; spherical LID (c), EUCLID (e) in critical alignment. The scale bar is 200μm.
Table 2.
Radii of uniformity regions.
Fig 5.
Pseudo RGB images (top) and respective spectral deviation %, across the horizontal cross section (bottom). Direct LEDs (a), Spherical LID (b), EUCLID (c) in Koehler alignment. Contrasts are enhanced for better visualisation. The scale bar is 200μm.
Fig 6.
Pseudo RGB images of fiber facet.
Output of EUCLID (a) and direct LEDs (b) are coupled to the input end of the fiber. The scale bar is 200μm.