Xiangmei Dong

Multifocus with small size, uniform intensity, and nearly circular symmetry.

We investigate in detail the focusing properties of the composite vector beam (CVB) composed of two orthogonally linearly polarized beams with inhomogeneous polarization modulation. By optimizing the modulation factor, a multifocus with excellent quality is obtained, where the sizes of each focus are fairly smaller than that of the focusing spot of a radially polarized beam, the uniformity in the intensity of the focal spots is as high as 1, and the distributions of each focal spot have nearly circular symmetry. In order to decrease the power loss of the incident beam, the CVB formed by an annular beam is demonstrated as the substitute for the optimized CVB formed by a Gaussian beam. This work is important for high-resolution and high-speed imaging in biology and micro-nanofabrication.

Control of the multifocal properties of composite vector beams in tightly focusing systems

The numbers of the focal spots and the dominant field (i.e., whether the axial field or the transverse fields play dominant role in the focusing field) have significant effects on various applications. In this paper, we have derived the universal imaging model of the composite vector beam (CVB) composed of two orthogonally linearly polarized beams with inhomogeneous polarization modulation, which is also suitable for various polarized beams, such as linearly, circularly, radially, azimuthally, and vortex polarized beams. Moreover, the sin&cos amplitude modulation with arbitrary orders and the pupil filters with cylindrical symmetry are also involved in this imaging model. On the basis of this imaging model, the regulars to control the focal numbers and the dominant field are drawn. For the various applications, some important conclusions and constructive advices are given.

Design and experimental study of the readout optical system in a multilayered waveguide memory

Readout optical technique is very important for the multilayered waveguide optical memory, which is based on an optical waveguide principle and a promising subject in the optical storage field compared to other 3D optical memory techniques. In this paper, the readout illumination system is designed by geometrical optical method and the experiment shows that the system works well.

The theoretic model of the waveguide single-layer optical memory

The waveguide multilayer optical memory is a novel and promising subject in the optical storage field compared with other 3D optical memory techniques. To our certain knowledge, how to establish the information scattering model of the single-layer waveguide optical memory is not found. In this paper, the Lippman-Schwinger equation and dyadic Greens function are used to compute an exact solution of the wave equation about the single-layer plane waveguide with information recorded. Then, the constructing method of the dyadic green function of the perfect plane waveguide with three layered structures is presented. Among the numerical calculations, a method about double integration of rapidly oscillatory function is introduced in detail. Based on the above method, the information scattering model of the waveguide single-layer optical memory will be constructed. According this theoretic model, with the computer simulation, the scattered light intensity distribution on the detector plane is showed. The scattering light intensity of the single information pit that is on behalf of information is also given.