Yurdakul, CelalettinÜnlü, M. Selim2021-05-122020-12-01Celalettin Yurdakul, M Selim Ünlü. 2020. "Computational nanosensing from defocus in single particle interferometric reflectance microscopy." Opt Lett, Volume 45, Issue 23, pp. 6546 - 6549. https://doi.org/10.1364/OL.4094581539-4794https://hdl.handle.net/2144/42545Single particle interferometric reflectance (SPIR) microscopy has been studied as a powerful imaging platform for label-free and highly sensitive biological nanoparticle detection and characterization. SPIR's interferometric nature yields a unique 3D defocus intensity profile of the nanoparticles over a large field of view. Here, we utilize this defocus information to recover high signal-to-noise ratio nanoparticle images with a computationally and memory efficient reconstruction framework. Our direct inversion approach recovers this image from a 3D defocus intensity stack using the vectorial-optics-based forward model developed for sub-diffraction-limited dielectric nanoparticles captured on a layered substrate. We demonstrate proof-of-concept experiments on silica beads with a 50 nm nominal diameter.p. 6546 - 6549en-US© 2020 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited.OpticsOptical physicsQuantum physicsElectrical and electronic engineeringArticle10.1364/OL.409458576056