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Two kinds of binary optical elements used in multi-channel one-dimensional Fourier spectrum analysis are introduced. One is equivalent to two overlapped line-type zone plates that are in two different orientations, and the other is composed of a line-type zone plate and a circular zone plate. In the output plane, the designed elements can simultaneously perform one-dimensional imaging of the input object in one direction and one-dimensional Fourier transformation in the perpendicular direction, respectively. Consequently, a series of one-dimensional spectra along different sectional lines of the object can be produced in the output plane. The elements are fabricated using the binary optical technique. Experiments show that these binary optical elements work well and are suitable for lensless optical processing systems.

We have proposed a novel principle for design of the binary Gabor zone plate (GZP) that can produce the desired focal-plane curves. The modified GZP can be fabricated as easily as the Fresnel zone plate (FZP). The proposed GZP has great flexibility in terms of manipulating the focusing properties. Optical experiments have confirmed the reliability of the GZP in focusing light into the specified area. The investigation on the factors affecting the performance of the GZP is presented. The low cost and easy production of the element show that it can serve an alternative to refractive lens in the short wavelength region where refractive optics is not applicable owing to possible strong absorption.

A self-focusing matched filter is proposed in this paper. The filter function is constructed by adding a quadratic phase factor to the conjugate Fourier spectrum of an object to be recognized. The filter is recorded by using computer-generated holographic techniques. Because of the property of self-focusing, the optical path of the recognition system becomes much simpler and is convenient to adjust. The experiments on the pattern recognition are performed. It is shown that this filter is suitable for recognizing the objects with different scales.

In this paper we introduce a new phase type combined optical element. The element is combined with Dammann grating and Fresnel zone plate in the same substrate by microelectronics technique, hence it has splitting functions of the Dammann grating and self-focusing function of the Fresnel plate. It can produce uniform multiple images by itself. We experimentally designed and fabricated an 9x9 multiple image element, and results show that the element can realize the multiple images we require and the intensity of each image is the same. Relative error is less than 5%.

A new type of diffractive optical bar code produced by computer-generated holographic technology is proposed. The message in the proposed bar code is hidden in the diffracted light of the bar code element and can be read from the first diffraction order. In contrast to the conventional hidden bar code, which needs a lens to focus the diffracted light, the proposed hidden bar code has a property of self-focusing. This self-focusing ability is achieved by modulating a function of the Fresnel zone plate into the bar code format. Consequently, the read-out process for the information in this hidden bar code avoids the use of a lens. Experiments have shown the feasibility of the proposed bar code and confirmed that it can perform better than the conventional hidden bar code.

A new type of computer-generated hologram (CGH) is described in this research. Upon the base of a two-channel CGH, it can generate four independent images in four different directions with the addition of positive or negative quadratic phase factors on the object spectrum; it has the character of self-focus. Results of the experiment are provided.