3D printed optical concentrators for LED arrays.

Additive manufacturing methods based on photopolymerization offer a promising potential for fabrication of high quality, highly transparent optical components. One use of these technologies involves fabrication of parts for very specific and narrow applications. In this work, we first performed optical raytracing simulations to model an optimized freeform nonimaging concentrator for a custom-built 12-LED array and then fabricated several waveguide concentrators using 3D printing and characterized their optical characteristics. Our results demonstrate that realizing an irradiance of 17 kW/m2 or more with an irradiance nonuniformity of better than 2 % over an area approaching 1 cm2 is realistic and that such an approach can rival intensities achieved with powerful lasers over a similar area. We also discuss an application where eight different types of LEDs were coupled into the waveguides to construct a solar simulator.