We present a new method for recording off-axis digital Fourier holograms of three-dimensional objects under spatially incoherent illumination. The method is implemented by modifying the optical configuration of triangular interferometer. The recording properties and 3D reconstruction ability of the proposed method are investigated theoretically and experimentally. Multicolor holographic recording and reconstruction of spatially incoherent illuminated object are achieved by using the proposed off-axis Fourier triangular interferometer and monochromatic digital camera. Only three holograms are sufficient to rebuild a color image without zero-order and twin image disturbing effect. Combining with some image fusion skills during reconstruction, the reconstructed color images with satisfied quality are demonstrated.

Integrated photonic devices and artificial intelligence have presented a significant opportunity for the advancement of optical computing in practical applications. Optical computing technology is a unique computing system based on optical devices and computing functions, which significantly differs from the traditional electronic computing technology. On the other hand, optical computing technology offers the advantages such as fast speed, low energy consumption, and high parallelism. Yet there are still challenges such as device integration and portability. In the burgeoning development of micro–nano optics technology, especially the deeply ingrained concept of metasurface technique, it provides an advanced platform for optical computing applications, including edge detection, image or motion recognition, logic computation, and on‐chip optical computing. With the aim of providing a comprehensive introduction and perspective for optical computing metasurface applications, we review the recent research advances of optical computing, from nanostructure and computing methods to practical applications. In this work, we review the challenges and analysis of optical computing metasurfaces in engineering field and look forward to the future development trends of optical computing.

Fast and noise-suppressed incoherent coded aperture correlation holographic imaging is proposed, which is utilized by employing an annular sparse coded phase mask together with adaptive phase-filter cross-correlation reconstruction method. Thus the proposed technique here is coined as adaptive interferenceless coded aperture correlation holography (AI-COACH). In AI-COACH, an annular sparse coded phase mask is first designed and generated by the Gerchberg-Saxton algorithm for suppressing background noise during reconstruction. In order to demonstrate the three-dimensional and sectional imaging capabilities of the AI-COACH system, the imaging experiments of 3D objects are designed and implemented by dual-channel optical configuration. One resolution target is placed in the focal plane of the system as input plane and ensured Fourier transform configuration, which is employed as reference imaging plane, and moved the other resolution target to simulate different planes of a three-dimensional object. One point spread hologram (PSH) and multiple object-holograms without phase-shift at different axial positions are captured by single-exposure sequentially with the annular sparse CPMs. A complex-reconstruction method is developed to obtain adaptively high-quality reconstructed images by employing the cross-correlation of PSH and OH with optimized phase filter. The imaging performance of AI-COACH is investigated by imaging various type of objects. The research results show that AI-COACH is adaptive to different experimental conditions in the sense of autonomously finding optimal parameters during reconstruction procedure and possesses the advantages of fast and adaptive imaging with high-quality reconstructions.

Motivated by the key role of point spread function in an imaging system, we propose an interferenceless coded aperture correlation holographic (I-COACH) technology with low speckle and high energy efficiency annular sparse coded phase mask (CPM) as system pupil to improve imaging performance. In the proposed method, a modified Gerchberg–Saxton (GS) algorithm is proposed to obtain a low speckle and high energy efficiency annular sparse CPM and to suppress speckle and increase the intensity of the holograms. Therefore, the randomly distributed amplitude in the bandwidth of the GS algorithm is replaced by the annular amplitude to determine the spatial position, and the band-limited random phase and quadratic phase are used as the initial phase to approximately meet band-limited conditions; meanwhile, in the iterative process of the algorithm, appropriate constraints are imposed on the information within and outside the band limit. All are used for obtaining the CPM with low speckle and high energy efficiency. Therefore, the proposed technique here is coined as low speckle I-COACH owing to the characteristics of CPM and imaging performances. The experimental results show that, under the same experimental conditions, the proposed method can obtain holograms with low speckle and intensity enhancement of about 8%, and further improve the quality of reconstructed images due to the improvement signal-to-noise ratio (SNR) of the holograms. The proposed method provides a powerful reference method for further expanding the I-COACH system to the field of low-intensity optical signals detection and imaging.

Three-dimensional imaging in biological samples usually suffers from performance degradation caused by optical inhomogeneities. Here we proposed an approach to adaptive optics in fluorescence microscopy where the aberrations are measured by self-interference holographic recording and then corrected by a post-processing optimization procedure. In our approach, only one complex-value hologram is sufficient to measure and then correct the aberrations, which results in fast acquisition speed, lower exposure time, and the ability to image in three-dimensions without the need to scan the sample or any other element in the system. We show proof-of-principle experiments on a tissue phantom containing fluorescence particles. Furthermore, we present three-dimensional reconstructions of actin-labeled MCF7 breast cancer cells, showing improved resolution after the correction of aberrations. Both experiments demonstrate the validity of our method and show the great potential of non-scanning adaptive three-dimensional microscopy in imaging biological samples with improved resolution and signal-to-noise ratio.