Activities

Recently, the wide spread of communication network so called Internet promotes the needs for the development of communication technologies. Among them, the optical communication technologies using optical devices such as optical fiber, optical switch, etc. are becoming the main technology for the communication and it is obvious that they must be further important in the near future. The investigations of the optical properties of materials are not only very important as the basic science supporting the optical technology but very fascinating as fundamental physics.

The field we are studying can be expressed briefly as ``Experimental investigation of optical properties of materials using LASER''. They include phenomena such as light absorption, reflection and scattering. Light emissions from the material after the absorption of light are also investigated. Such emissions are different from the incident light in wavelength and they are called luminescence or fluorescence. The photo-conductivity is also one of the means of investigation.

The materials we investigate widely cover liquid, insulator, semiconductor, super-lattice, etc. The main subjects we are handling now are,

1. Nonlinear effects of semiconductors under strong excitation.
2. Exciton optics of super-lattice made of semiconductor or insulator.
3. Excitation and lattice distortion of localized state in semiconductor.
4. Electron momentum relaxation studied by cyclotron resonance.
5. Studies on quantum mechanical coherence in optical processes.

etc.