Optimal design of incoherent tunable-frequency structured illumination microscope scheme

Structured illumination microscopy (SIM) improves resolution and optical sectioning capability compared to conventional widefield techniques. The main idea of this method is the illumination of the sample with a structured pattern of fixed spatial modulation frequency. Previously, a Fresnel biprism has been implemented in a structured illumination (SI) device providing tunable-frequency sinusoidal patterns. However, the use of this SI system introduces a tradeoff between the visibility and field of view of the illumination fringes. In this contribution, we analyze theoretically this tradeoff and propose the optimal design for the Fresnel biprism-based SIM system.