Yoshiji Suzuki

Three-dimensional microscopy by optical scanning holography

We first briefly review a new 3-D imaging technique called optical scanning holography (OSH). We then discuss the techniques 3-D holographic magnification in the context of optical scanning and digital reconstruction. Finally, we demonstrate the 3-D imaging capability of OSH by holographically recording two planar objects at different depths and reconstructing the hologram digitally.

Transfer characteristics of the microchannel spatial light modulator

The microchannel spatial light modulator (MSLM) is a versatile optically addressed spatial light modulator for optical computing and the optical neural network. In this paper the transfer characteristics of the MSLM are presented. The addressability and readability of the device and their relationships are discussed theoretically and experimentally from the viewpoint of the device structure and performance.

Twin-image elimination experiments for three-dimensional images in optical scanning holography

Twin-image elimination in the context of optical scanning holography has recently been proposed. The proposed technique involves simultaneously acquiring sine and cosine Fresnel holograms. A complex hologram is then formed by complex addition of the holograms, and twin-image rejection is predicted by computer simulations. An experimental verification of the technique by optical acquisition of the two holograms and subsequent reconstruction of the complex hologram digitally is reported. Three-dimensional image reconstruction without twin-image noise is demonstrated.

Optical scanning holography

This paper provides a tutorial on the principles of holography, followed by a review of a newly developed 3-D imaging technique in which 3-D optical information of an object cam be extracted by a 2-D optical scan of the object. The technique is called optical scanning holography (OSH). In the context of optical scanning holography, we discuss some of its potential applications such as holographic information transmission and television (TV) system, 3-D image coding and decoding, 3-D microscopy, and 3-D optical remote sensing. In most cases, feasibility has been proven but awaits broader application.

Optical associatron: a simple model for optical associative memory.

A new neural network architecture for optical computing is proposed. This architecture can be used for implementing a simple system based on a modified theory of the associative memories. It is shown that the memorized patterns can be recalled perfectly by an experimental system using two microchannel spatial light modulators. The modified theory and principle of operation of the optical associatron system are discussed, and the system itself and basic experimental results are also described.

Real-time two-dimensional holographic imaging by using an electron-beam-addressed spatial light modulator.

A real-time electron-beam-addressed spatial light modulator-based holographic imaging system has recently been proposed. We present results of two-dimensional holographic imaging and further demonstrate that the proposed system can be readily adaptable to automation by using digital computers for robust holographic imaging. Specifically, by nonlinear processing of a digitally stored hologram, fringe contrast enhancement has been achieved.

Experimental studies on learning capabilities of optical associative memory

The learning capabilities of optical associative memory called the optical associatron are experimentally shown. The experimental system has a simple architecture for optical associative memory; in particular, the system has versatile adaptive learning capabilities implemented with microchannel spatial light modulators. In this paper, various experimental results of learning and recalling processes on the system are shown. Based on the results, the behavior of learning on the optical associative memory is discussed. In addition, a modified method of learning is proposed and verified on the system. A method for implementation of error backpropagation is also proposed.

A Spatial Light Modulator

Publisher Summary This chapter discusses spatial light modulator, which comprises a photocathode, micro channel plate, mesh electrode, and a LiNbO3 crystal in a vacuum-sealed tube. The device is a transducer for incoherent to coherent light conversion; it is highly sensitive and can be used over a wide wavelength range. It can also be used to perform a variety of image processing. When an incoherent input optical image is incident on the photocathode, it creates a photoelectron image. This electric charge image is deposited onto the surface of the electrooptic crystal after electron multiplication by 103 to 104 in the MCP. This electric charge creates a change in the electric field across the crystal. Control of the charge on the surface of the crystal is performed by the use of the secondary electron emission characteristics of the SiO2 layer.

A 400 Anode Chevron Microchannel Plate PMT for High Energy Application

A proto type multianode photomultiplier tube incorporating a chevron type MCPs electron multiplier and 400 multi anodes was developed for high speed image pick-up at low light levels such as in detection of rings of Cherenkov light. The diameter of and mean spacing of each anode are 0.3mm and 0.65mm respectively in a rectangular array of 16mm×12mm. The MCP used in the tube were fabricated at HTV and had 24.9mm diameter, 20mm useful diameter, 15¿m pore diameter and 45 length to pore diameter ratio. Electron multiplication and dark current for each MCP were about 104 and 1pA at 1000v respectively. 0.6mm spatial resolution over anode surface and about 600psec rise time of output signal were obtained.

Twin-image elimination in optical scanning holography

We propose a novel multiplexing technique to solve the twin image problem in optical scanning holography without the use of a spatial carrier, as commonly used in conventional off-axis holography. The technique involves simultaneously acquiring sine and cosine Fresnel zone-lens plate coded images by optical scanning. A complex addition of the two coded images will then be performed and decoded to give a twin-image rejection reconstruction. Computer simulations will be presented to demonstrate the validity of the idea.