title: Ultra-compact on-chip LED collimation optics by 3D femtosecond direct laser writing.
abstract: By using two-photon lithographic 3D printing, we demonstrate additive manufacturing of a dielectric concentrator directly on a LED chip. With a size of below 200 μm in diameter and length, light output is increased by a factor of 6.2 in collimation direction, while the emission half-angle is reduced by 50%. We measure excellent form fidelity and irradiance patterns close to simulation. Additionally, a more complex shape design is presented, which exhibits a nonconventional triangular illumination pattern. The introduced method features exceptional design freedoms which can be used to tailor high-quality miniature illumination optics for specific lighting tasks, for example, endoscopy.
authors.forename: Simon
authors.initials: S
authors.lastname: Thiele
authors.forename: Timo
authors.initials: T
authors.lastname: Gissibl
authors.forename: Harald
authors.initials: H
authors.lastname: Giessen
authors.forename: Alois M
authors.initials: AM
authors.lastname: Herkommer