Digital holographic microscopy for automated 3D cell identification: an overview (Invited Paper)

Digital holographic （DH） microscopy is a promising technique for quantitative phase contrast imaging. It provides complex amplitude of the object wavefront, which in turn yields the thickness distribution of the object. An added advantage of the technique is its ability for numerical focusing, which provides the thickness distribution of the object at different axial planes. In this invited paper, we present an overview of our reported work on two beam DH microscopyto acquire different cell parameters for cell imaging and automated cell identification. Applications to automated cells and automated identification of malaria infected red monitoring of stem cells without destroying the blood ceils are discussed.     

Progress on waveguide-based holographic video(Invited Paper)

This paper presents progress on the characterization of guided-wave light modulators for use in a low-cost holographic video monitor based on the MIT scanned-aperture architecture. A custom-built characterization apparatus was used to study device bandwidth, RGB operation, and linearity in an effort to identify optimal parameters for high bandwidth, GPU-driven, full-color holographic display.     

Color holographic display based on azo-dye-doped liquid crystal (Invited Paper)

A multiplexed holographic display video has been achieved by using a passive azo-dye-doped liquid crystal （LC） cell. Holograms formed in this cell can be refreshed in the order of several milliseconds. By angular multiplexing technique, dynamically multiplexed holographic videos are realized. Moreover, the reconstructed RGB images are merged into a color image, which illustrates the possibility of a color holographic three-dimensional （3D） display by holographic multiplexing of the LC cell.     

Time-division multiplexing holographic display using angular-spectrum layer-oriented method(Invited Paper)

A time-division multiplexing method for computer-generated holograms(CGHs) is proposed to solve the problem of the limited space-bandwidth product. A three-dimensional(3-D) scene is divided into multiple layers at different depths. The CGH corresponding to each layer is calculated by an angular-spectrum algorithm that is effective at a wide range of propagation distances. All of the CGHs are combined into several group-CGHs.These group-CGHs are sequentially uploaded onto one spatial light modulator at a high frame rate. The spacebandwidth product can be benefited by the time-division processing of the CGHs. The proposed method provides a new approach to achieve high quality 3-D display with a fast and accurate CGH computation.     

Real-time pupil tracking backlight system for holographic 3D display (Invited Paper)

We propose an automatic three-dimensional(3D)pupil tracking backlight system for holographic 3D display system with large image size and full-parallax accommodation effect.The proposed tracking module is applied to a holographic 3D display system with two sets of directional holographic imaging module composed of 2×2 large scale lens array and 22-inch high-resolution liquid crystal display 3D panel.System architecture is described and experimental results are presented.     

Three-dimensional display technologies in wave and ray optics: a review (Invited Paper)

Multiple three-dimensional （3D） display technologies are reviewed. The display mechanisms discussed in this paper are classified into two categories： holographic display in wave optics and light field display in ray optics, which present the 3D optical wave field in two different ways. Key technical characteristics of the optical systems and the depth cues of human visual system are analyzed. It is to be expected that these 3D display technologies will achieve practical applications with the increase of the optical system bandwidth.     

Data information transfer using complex optical fields:a review and perspective(Invited Paper)

Tailored complex optical fields,may find applications in optical manipulation,imaging,microscopy,quantum information processing,and optical communications.Here,we focus on data information transfer for optical communications using complex optical fields.We review recent research progress in complex optical field modulation,multiplexing,and multicasting for data information transfer on different platforms of waveguides,free space,and fiber.Challenges and perspectives are also discussed.     

Data-embedded-error-diffusion hologram (Invited Paper)

This paper describes a method for converting a complex Fresnel hologram into a phase-only hologram that can be embedded with large amount of data. Briefly, each row of pixels in the hologram is scanned sequentially in a left-to-right direction. The magnitude of each visited pixel is set to a constant, and its phase is embedded with the data. Subsequently, the error is diffused to the neighborhood pixels. The phase hologram realized with such means, which is referred to as the data-embedded-error-diffusion （DEED） hologram, is capable of preserving high fidelity on the content of the hologram and the embedded data.     

Advances in the light field displays based on integral imaging and holographic techniques (Invited Paper)

Light field displays comprise three-dimensional （3D） visual information presentation devices capable of providing realistic and full parallax autostereoscopic images. In this letter, the recent advances in the light field displays based on integral imaging （II） and holographic techniques are presented. Several advanced approaches to demonstrate the light field displays including viewing angle enhancement techniques of the II display, a fast hologram generation method using graphics processing unit （GPU） and multiple WRPs, and a holographic microscopy to display the living cells are reported. These methods improve some important constraints of the light field displays and add new features.     

Optical Network Optimization(Invited Paper)

A novel low-complexity framework for designing survivable optical mesh networks with undetermined topology is presented. By jointly optimizing the topology planning, working- and spare-capacity planning, a cost saving of over 40% can be achieved for a national-scale network with 31 nodes.     

Fresnel incoherent correlation hologram—— a review （Invited Paper）

Holographic imaging offers a reliable and fast method to capture the complete three-dimensional （3D） information of the scene from a single perspective. We review our recently proposed single-channel optical system for generating digital Fresnel holograms of 3D real-existing objects illuminated by incoherent light. In this motionless holographic technique, light is reflected, or emitted from a 3D object, propagates through a spatial light modulator （SLM）, and is recorded by a digital camera. The SLM is used as a beamsplitter of the single-channel incoherent interferometer, such that each spherical beam originated from each object point is split into two spherical beams with two different curve radii. Incoherent sum of the entire interferences between all the couples of spherical beams creates the Fresnel hologram of the observed 3D object. When this hologram is reconstructed in the computer, the 3D properties of the object are revealed.     

Talbot holographic illumination nonscanning (THIN) fluorescence microscopy

Optical sectioning techniques offer the ability to acquire three‐dimensional information from various organ tissues by discriminating between the desired in‐focus and out‐of‐focus (background) signals. Alternative techniques to confocal, such as active structured illumination, exist for fast optically sectioned images, but they require individual axial planes to be imaged consecutively. In this article, an imaging technique (THIN), by utilizing active Talbot illumination in 3D and multiplexed holographic Bragg filters for depth discrimination, is demonstrated for imaging in vivo 3D biopsy without mechanical or optical axial scanning.     

Uncertainty,certainty, and relativity(Invited Paper)

One of the most fascinating principles in quantum mechanics must be Heisenberg's uncertainty principle, which can be briefly stated as follows: every physical observation cannot be precisely determined without some degree of error or uncertainty. And it is by no means can one use the principle within the limit of certainty region, as will be shown in this Letter. Two of the most important pillars in modern physics must be Einstein's relativity theory and Schr?dinger's contribution to quantum mechanics. Yet, there is a profound connection between these discoveries by means of the uncertainty relationship, in which we shown that the observation of a high-speed object is conceivable if the speed of the observer keeps up with object's speed.     

From first fibers to mode-division multiplexing(Invited Paper)

This Review focuses on optical transmission fibers and the high-capacity systems operating thereon. It attempts to combine key lessons learned from the 50-year history of low-loss optical fibers with views on future fiber and systems requirements, discussing likely evolution paths and potential pitfalls in resolving the optical network capacity crunch.     

Computer generated hologram from full-parallax 3D image data captured by scanning vertical camera array (Invited Paper)

Full-parallax light-field is captured by a small-scale 3D image scanning system and applied to holographic display. A vertical camera array is scanned horizontally to capture full-parallax imagery, and the vertical views between cameras are interpolated by depth image-based rendering technique. An improved technique for depth estimation reduces the estimation error and high-density light-field is obtained. The captured data is employed for the calculation of computer hologram using ray-sampling plane. This technique enables high-resolution display even in deep 3D scene although a hologram is calculated from ray information, and thus it makes use of the important advantage of holographic 3D display.     

Optical Waveguide Switches Employing Total-Internal-Reflection (TIR) Effect (Invited Paper)

In this paper, our recent research work on the total-internal-reflection optical switch is presented. The thermo-optic effect of polymeric materials and the photon-induced carrier effect of GaAlAs/GaAs are used in our devices.     

Ultra-broadband access enabled by fiber optics(Invited Paper)

The advent of low loss optical fiber has consistently led us to the ultra-broadband era, where bandwidths exceeding 1 Gb/s are commonplace. This Review reviews the early history of fiber access, pointing out some of the lasting design choices and signature features of fiber access. The progress of the various passive optical network technologies is also reviewed, and some views regarding the future trends of fiber in the access.     

Holographic display based on compressive sensing (Invited Paper)

We propose a method to improve the quality of the reconstructed images based on compressive sensing principles. The pseudo-inverse matrix and the total variation minimization algorithms are combined to reduce the sampling number of the computer generated hologram. Numerical simulations are performed and the results indicate that the peak signal to noise ratio is increased and the sampling ratio is decreased at the same time for holographic display.     

Highly adjustable helical beam:design and propagation characteristics(Invited Paper)

Light fields with extraordinary propagation behaviors,such as nondiffracting and self-bending,are useful in the optical delivery of energy,information,and even objects.A kind of helical beam is constructed here based on the caustic method.With the appropriate design,the main lobe of these helical beams can be both well-confined and almost nondiffracting,while moving along a helix with its radius,period,number of rotations,and main lobes highly adjustable.In addition,the peak intensity of the main lobe fluctuates below 15%during propagation.These promising characteristics may enable a variety of potential applications based on these beams.     

Flexible generation of femtosecond cylindrical vector beams(Invited Paper)

Femtosecond(fs)cylindrical vector beams(CVBs)have found use in many applications in recent years.However,the existing rigid generation methods seriously limit its development.Here,we propose a flexible method for generating fs-CVBs with arbitrary polarization order by employing half wave plates and vortex retarders.The polarization state,autocorrelation width,pulse width,and spectrum features of the input and generated CVB pulses are measured and compared.The results verify that the generated CVBs remain in the fs regime with no appreciable temporal distortion,and the energy conversion efficiency can reach as high as 96.5%,even for a third-order beam.As a flexible way to generate fs-CVBs,this method will have great significance for many applications.