Low-Cost 3D Printed Optics for Super-Resolution Multifocal Structured Illumination Microscopy

We present a low-cost 3D printing method of fabricating optical quality lenslet arrays for integration in a multifocal structured illumination microscope (mSIM), achieving fluorescence imaging below the optical diffraction limit. We detail the design and manufacturing processes to produce high-quality 3D printed optics, showing their comparable surface roughness of 30 ± 2.5 nm for the 3D printed elements compared to 37 ± 1.4 nm for commercial glass optics. A 3D printed lenslet array with a ‘honeycomb’ geometry and 1.2 mm lenslet diameter was compared to a high-end glass commercial lenslet array with 250 µm lenslet diameter and a lower cost commercial lenslet array with a 1.2 mm by 1.6 mm lenslet footprint. The imaging performance of the different optics was benchmarked using a custom mSIM setup by quantifying the beam profile homogeneity and the experimental lateral resolution. The mSIM setup incorporating the different microlens arrays was tested using a commercial bovine pulmonary artery endothelial cell specimen, highlighting an achievable resolution enhancement from 229 nm ± 11 nm with widefield illumination to 137 ± 11 nm using the high-end commercial microlens array and 134 nm ± 9 nm using the 3D printed honeycomb lenslet array. Advantages of improved background rejection through the custom lenslet geometry are discussed, highlighting the super-resolution microscope performance achievable through custom low-cost 3D printed optics.