Adaptive coded phase mask design and high-quality image reconstruction for interference-less coded aperture correlation holography.

The interference-less coded aperture correlation holography is a non-scanning, motionless, and incoherent technique for imaging three-dimensional objects without two-wave interference. Nevertheless, a challenge lies in that the coded phase mask encodes the system noise, while traditional reconstruction algorithms often introduce unwanted surplus background components during reconstruction. A deep learning-based method is proposed to mitigate system noise and background components simultaneously. Specifically, this method involves two sub-networks: a coded phase mask design sub-network and an image reconstruction sub-network. The former leverages the object's frequency distribution to generate an adaptive coded phase mask that encodes the object wave-front precisely without being affected by the superfluous system noise. The latter establishes a mapping between the autocorrelations of the hologram and the object, effectively suppresses the background components by embedding a prior physical knowledge and improves the neural network's adaptability and interpretability. Experimental results demonstrate the effectiveness of the proposed method in suppressing system noise and background components, thereby significantly improving the signal-to-noise ratio of the reconstructed images.

Depth multiplexing in an orbital angular momentum holography based on random phase encoding.

The orbital angular momentum (OAM) holography has been identified as a vital approach for achieving ultrahigh-capacity in 3D displays, digital holographic microscopy, data storage and so on. However, depth has not been widely applied as a multiplexing dimension in the OAM holography mainly because of the serious coherence crosstalk between different image layers. The multi-layered depth multiplexing OAM holography is proposed and investigated. To suppress the coherence crosstalk between different image channels, random phases are used for encoding different image layers separately. An image can be reconstructed with high quality at a specific depth from an appropriate OAM mode. It is demonstrated that the depth multiplexing of up to 5 layers can be achieved. This work can increase the information capacity and enhance the application of the OAM holography.