RESEARCH INTERESTS

Nonlinear Photorefractive Materials

Personal research is focused on the nonlinear photorefraction, in which the fields include the materials, characterizations and applications.

1. Materials

One of the main problems in the photorefractive technology is the material, in which the properties are still not good enough for the practical application. Searching for good materials is then an important topic. BaTiO3, one of the best photorefractive materials, is grown by the top-seeded solution method. To optimize its properties, the impurity doping and annealing are used and investigated.

2. Characterizations

Characterizations included the two beam coupling, photoinduced decay and dark decay. These can induce the properties of two beam coupling gain, speed, dark conductivity and the competition between the deep and shallow traps. From these information, the role of impurity doping and annealing can be explored.

3. Photorefractive theory

Photorefractive theory was basically built in 1980. In the last ten years, some new models were introduced to modify the traditional theory. One of the main modifications is the role and effect of shallow trap, which is existed with the deep trap. In the last few years, the reaseach is on the origin of the photorefractive effect. The spectroscopic technique then became an important tool in this field. Recently, we introduced that the carrier type changes with the incidient wavelength. From the investigation of spectroscopy, the role of the energy level was deduced.

4. Applications

The photorefractive applicaitons include optical information processing, optical compution and laser, etc. These work are cooperated with other reseachers. （ Professor Yau and Sun ） , mainly on the optical storage, interferometer and phase conjugation.

LABORATORY