Holographic optical coherence imaging

Abstract

This chapter gives an overview of the principles of holographic OCI. It begins with a description of off-axis holography as spatial heterodyne detection and continues with the origin and role of speckle in multichannel illumination of tissue. Image-domain holography (IDH) and Fourier–domain holography (FDH) are described. Holography in the Fourier domain has the capability for phase–contrast imaging that can acquire small sub–wavelength displacements despite long coherence length. The trade–offs between photorefractive and digital holography are discussed. The chief biological target is multicellular spheroids, specifically rat osteogenic sarcomas that are grown in vitro. After describing the physiological and optical properties of these spheroids, results from holographic OCI are presented using both photorefractive and digital holography.