Non-interferometric phase retrieval for collinear phase-modulated holographic data storage

Abstract

Because of its simple optical system setup and robust noise tolerance, non-interferometric phase retrieval is an important technique for phase-modulated holographic data storage. Usually, the iterative algorithm of non-interferometry needs hundreds of iteration numbers to retrieve phase accurately, the data transfer rate decreases severely. Strong constraints such as adding embedded data into the phase data page can reduce the iteration numbers, but this method decreases the code rate severely. In this paper, we proposed the advanced non-interferometric phase retrieval method based on the collinear system. By encoding the reference beam of the collinear optical holographic storage system with embedded data, the storage space of the signal beam data page is completely released and the encoding rate is doubled. The embedded data can provide more modulation index including phase and amplitude to shorten iterations, so the data transfer rate is also increased. In the simulation, we recorded a four-level phase pattern and retrieved the phase correctly.

Diffractive Deep-Neural-Network-Based Classifier for Holographic Memory

“…That is, the white areas of the signal pattern and the circular reference pattern have π-radian and the other black areas have zero-radian phase modulation. Such phase-limited collinear holographic memory has been used in, e.g., [35].…”