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One of the most important advantages of optical manufacturing by 3D printing is the high degree of freedom in geometry and optical design. This is especially true for fabrication methods like stereolithography which, in contrast to jet or extrusion based methods, usually enable true 3D geometries with undercuts and buried cavities. In case of multiphoton lithography such complex designs can additionally be manufactured with sub-wavelength feature sizes in all three dimensions. This enables optical designs with unmatched complexity combining reflective, refractive and diffractive surfaces as well as structures like photonic crystals in all 3 dimensions.
In this work we introduce different strategies to show how the barely restricted design space can be used to realize compact 3D-printed micro-optics with strong optical performance. Different types of concentration and beam shaping devices for non-imaging purposes are introduced and refractive, diffractive, reflective and hybrid variants are discussed. While these devices serve to transfer one light distribution into another they are not suited for direct imaging.
In order to image extended objects, lenses or lens systems are commonly optimized for a maximum space-bandwidth product which is connected to the product of imaging numerical aperture and image height. The space-bandwidth product is also correlating with the number of distinguishable image points which are transferred through a system. We demonstrate how maximum space-bandwidth product multi-lens optical systems can be designed and realized. Different variants of refractive, purely diffractive and hybrid imaging systems with lens barrel diameters below 500 µm are demonstrated and compared in terms of optical performance and manufacturability.
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