Coded aperture correlation holography (COACH) with a superior lateral resolution of FINCH and axial resolution of conventional direct imaging systems

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. (C) 2021 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

FINCH is a self-interference incoherent digital holography technique with higher lateral resolution than equivalent incoherent imaging systems but lower axial resolution. COACH is another incoherent holographic method with improved axial resolution but same lateral resolution as direct imaging. CAFIR, a variant of COACH, combines the improved lateral resolution of FINCH with the high axial resolution of direct imaging.