Six-pack holographic imaging for dynamic rejection of out-of-focus objects

• Published in: Optics express Vol. 29; no. 2; pp. 632 - 646
• Main Authors: Mirsky, Simcha K, Shaked, Natan T
• Format: Journal Article
• Language: English
• Published: United States 18.01.2021
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.411078

Six-pack holography is adapted to reject out-of-focus objects in dynamic samples, using a single camera exposure and without any scanning. By illuminating the sample from six different angles in parallel using a low-coherence source, out-of-focus objects are laterally shifted in six different directions when projected onto the focal plane. Then pixel-wise averaging of the six reconstructed images creates a significantly clearer image, with rejection of out-of-focus objects. Dynamic imaging results are shown for swimming microalgae and flowing microbeads, including numerical refocusing by Fresnel propagation. The averaged images reduced the contribution of out-of-focus objects by up to 83% in comparison to standard holograms captured using the same light source, further improving the system sectioning capabilities. Both simulation and experimental results are presented.