title: Axial standing-wave illumination frequency-domain imaging (SWIF).
abstract: Despite their tremendous contribution to biomedical research and diagnosis, conventional spatial sampling techniques such as wide-field, point scanning or selective plane illumination microscopy face inherent limiting trade-offs between spatial resolution, field-of-view, phototoxicity and recording speed. Several of these trade-offs are the result of spatial sampling with diffracting beams. Here, we introduce a new strategy for fluorescence imaging, SWIF, which instead encodes the axial profile of a sample in the Fourier domain. We demonstrate how this can be achieved with propagation-invariant illumination patterns that extend over several millimeters and robustly propagate through layers of varying refractive index. This enabled us to image a lateral field-of-view of 0.8 mm x 1.5 mm with an axial resolution of 2.4 µm - greatly exceeding the lateral field-of-view of conventional illumination techniques (~100 µm) at comparable resolution. Thus, SWIF allowed us to surpass the limitations of diffracting illumination beams and untangle lateral field-of-view from resolution.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Judkewitz
authors.forename: Changhuei
authors.initials: C
authors.lastname: Yang
mesh_terms: D004867:Equipment Design; D005453:Fluorescence; D006801:Humans; D008029:Lighting / Q000379:methods*; D018613:Microscopy, Confocal / Q000295:instrumentation*; D008856:Microscopy, Fluorescence / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*