Yunxia Wu

BOUNDARY DIFFRACTION METHOD FOR APERTURE NEAR-FIELD DIFFRACTION

The boundary diffraction method is introduced to analyze the near-field diffraction of a subwavelength aperture. A self-consistent formula of boundary diffraction suitable to near field is derived. The near-field diffraction patterns of slits and circular apertures are obtained. The influence of incident light polarization on these diffraction patterns is also shown. These results are in good agreement with other theoretical and experimental results.

The write strategy investigation of multi-level optical storage in azobenzene liquid crystal polymer film

With the increasing demand of optical storage capacity, multi-level (ML) optical storage based on multi-level-amplitude modulation is receiving more and more attention, for it transmits more information ove a fixed bandwidth channel by using the available SNR more efficiently. We proposed an ML optical storage technology in azo LCP film based on polarization angle division. In this paper, the write strategy is developed by a ML write-compensation system that corrects for non-linearities of the data signal. The dynamic transmittance range is extended with the full monotonic range of angle and the varaition of each amplitude level relative to our dynamic range is improved. The experiments of imroved linear and nonlinear 16-level storage in azo LCP are demonstrated. The effects of thickness non-uniformity on linear and nonlinear 16-level storage are discussed.

Self-injection-locking single frequency Yb-doped fiber ring laser

The self-injection locking single frequency Yb-doped fiber ring laser is reported. The system shows compact, stable and tunable. In the primary experiment, the Self-injection locking single frequency fiber ring laser with wavelength 1.05325)mum, power exceeding 3.5mW,line-width less than 36 MHz was manufactured. The laser shows stability, low threshold and high power. No mode-hopping was observed within 2 hours. The single polarization output can be obtained when use single polarization fiber.

Near-field optical imaging properties by passive and active fiber probes

Passive and active fiber probes, used for the scanning near- field optical microscope, show different image properties. For the passive fiber probe, a better optical image contrast has been obtained with a parabolic taper than with a linear taper. The reflected fields in different fiber tapers have been discussed. For the active fiber probe, an ASE probe made of Er3+-doped fiber has shown a higher efficiency of several times and a lower image noise than the usual passive probe.

Measurement for both vibration and deformation of microsurface by Fizeau interferometer of composite self-focus rod sensor

By using composite self-focus rod, LD-pumped frequency doubling Nd:YVO4 laser and 3D fine regulation stand, a new Fizeau-type interferometer is developed. It can apply to measuring the micro-vibration and deformation of micro- surface at the same time. The theoretical analysis and the experimental results for the interferometer of self-focus sensor are given.