Micro-optics have emerged as a cost-effective solution for increasing the photon collection efficiency of optoelectronic systems. By placing a microlens or microlens array (MLA) on top of the active area of a solar cell or photodetector, sustained improvements of up to 50% in the quantum efficiency of these devices have been demonstrated. However, current fabrication technologies for micro-optics can be limited in throughput, attainable geometries, fill-factor (FF) or range of suitable substrates. In this talk, I will present laser catapulting (LCP), a novel maskless laser additive manufacturing technique capable of customized and in-situ fabrication of polymeric micro-lenses over planar, curved and flexible substrates. LCP is based on a two-step process. First, a single laser shot is used to transfer a microdisk from a solid donor film directly to the area of interest on the optoelectronic device. Second, a thermal reflow process converts the disks into high-quality microlenses that exhibit almost perfect smoothness. Notably, closely packed MLA with a 100% FF can be obtained, not possible with standard direct-write methods such as inkjet printing or microdispensing. Furthermore, precise, accurate and high-throughput fabrication of lenses with different focusing power and geometries –spherical, cylindrical or even triangular – can be realized by simply adjusting laser parameters such as laser fluence or beam shape. I will present an in-depth experimental characterization of LCP, discuss the advantages and pitfalls of this technology and illustrate them with several applications, including enhancing the performance of single-photon avalanche diode (SPAD) arrays for super-resolution microscopy.
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