Abstract: Apparatuses and methods for investigating the inside of a tissue cell are disclosed. Embodiments include diffusely scattering light off a target sample, producing two crossing beams from the scattered light, and using a camera to create an image from the light. Some embodiments utilize a Fourier lens and a Fresnel biprism, and optionally include a long-coherence light source, a delay plate (which can be a polarization rotator or an optical flat), and/or a beam expander. Still further embodiments utilize a diffraction grating, a spatial filter (which may include two differently sized apertures), and a Fourier lens, and optionally include differently sized apertures in the spatial filter. Some embodiments include a transparent support and illuminating the target at an oblique angle through the transparent support. Still further embodiments utilize a low-coherence light source and/or immobilizing the sample tissue using surface bonding chemistry.