Quantitative Phase Imaging (QPI) provides unique means for the imaging of biological or technical microstructures, merging beneficial features identified with microscopy, interferometry, holography, and numerical computations. This roadmap article reviews several digital holography-based QPI approaches developed by prominent research groups. It also briefly discusses the present and future perspectives of 2D and 3D QPI research based on digital holographic microscopy, holographic tomography, and their applications.
Fresnel incoherent correlation holography (FINCH) is a self-interference incoherent digital holography technique. It possesses a higher lateral resolution than an equivalent incoherent imaging system. However, FINCH has lower axial resolution than the direct imaging systems with the same numerical aperture. A decade after the FINCH invention, a different incoherent holographic method named coded aperture correlation holography (COACH) was developed with improved axial resolution but with the same lateral resolution as direct imaging. In this study, we propose and demonstrate a variant of COACH called coded aperture with FINCH intensity responses (CAFIR) with an improved lateral resolution that is similar to the FINCH system while maintaining its high axial resolution similar to the direct imaging system. CAFIR is implemented with coded phase masks to generate an ensemble of quasi-randomly distributed FINCH-like responses. Point spread holograms and object holograms are recorded under identical conditions, and they are cross-correlated to obtain the image reconstruction. Imaging of a multiplane object is studied to compare the axial resolution of CAFIR with FINCH and direct imaging systems.
Optical, spatial, or temporal multiplexing is a well-known approach to optimize the performance of imaging systems. Following the recent discovery about the capability to record a coherent hologram in an interferenceless working mode, we propose a motionless method to spatially multiplex more than one hologram in a single camera exposure. Using the rather simple multiplexing framework based on coded aperture correlation holography, we effectively increase the acquisition rate of dynamic scenes and the holographic data compression by two-fold. Quantitative or qualitative phase microscopy and acquisition of a bipolar hologram from a single camera shot, experimentally confirm the applicability of the suggested technique.
Recently, a method of recording holograms of coherently illuminated threedimensional scene without two-wave interference was demonstrated. The method is an extension of the coded aperture correlation holography from incoherent to coherent illumination. Although this method is practical for some tasks, it is not capable of imaging phase objects, a capability that is an important benefit of coherent holography. The present work addresses this limitation by using the same type of coded phase masks in a modified Mach-Zehnder interferometer. We show that by several comparative parameters, the coded aperturebased phase imaging is superior to the equivalent open aperture-based method. As an additional merit of the coded aperture approach, a framework for increasing the system's field of view is formulated and demonstrated for both amplitude and phase objects. The combination of high sensitivity quantitative phase microscope with increased field of view in a single camera shot holographic apparatus, has immense potential to serve as the preferred tool for examination of biological tissues and micro-organisms.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.