1. symmetry Violation in Atomic system: Search for electric dipole moment of atomic system is to test the fundamental symmetry violation with a relative small scale atomic physics experiment. A slow atomic beam based on the laser cooling technique can largely reduce the systematic error due to vxE effect in the EDM measurement. Meanwhile, it can form a large area of periodical nano-structure using the atom lithography technique. In comparison with Cs and Rb, atomic thallium has a low vapor pressure and high stability in air, and could provide many interesting applications.

The laser sources (cw 377nm and 351nm) of frequency doubled Ti:Sapphire lasers, which were used to optical pumping and laser cooling atomic thallium, have been built. Recently, using a hot atomic beam, the transition frequency of thallium ground state 6P1/2 to 7S1/2 has been measured to high precision (200kHz). This result will be a benchmarker of the atomic structure calculation, and important to the PNC experiment.

2. Ultracold collision and cold molecule:This newly established experiment is to laser cool atomic K and Rb simultaneously to form a mixture. We are looking for a KRb molecule associated in the trap by photonassociation or Feshbach resonance. Many theoretical perditions about the peculiar behavior of ultra-cold dipolar molecule have been published (including the very large EDM effect). We have simultaneously produced both of K and Rb in our steanless chamber. Then, we will study the inter-species cold collision at first stage, and then form KRb molecule trapped in a optical potential well.

3. Precision atomic laser spectroscopy:
Rb 5S1/2->7S1/2 two-photon transition: We have first time observed this transition using a diode laser system. And, the transition frequencies have been measured to an uncertainty of 20kHz. It is a very good candidate of frequency standard in optical communication band.

Li 2S->3S two-photon spectroscopy: This ground state transition has been observed in our laboratory with Ti:Sapphire laser. The absolute frequency measurement will be taken soon. Lithium has a simple three-electron structure; the measurement can test the theoretical many-body calculation, and the isotope shift is also a probe of the lithium unclear structure. With frequency comb (in collaboration with Prof. Shy), our result can improve the accuracy by an order of magnitude, to the previous experiment of GSI, Germany.

Muonic hydrogen Lamb shift measurement: The international collaboration (Muonic hydrogen Lamb shift), including Taiwan, Switzerland, France, Germany, USA, and Portugal, is to measure the exotic atom--- muonic hydrogen 2s-2p Lam shift to determine the proton charge radius. Our main contribution in this experiment is on the laser system. The preliminary experimental run has been finished in 2004. The progress in laser system makes the continuity of experiment possible. A new thin disk laser will be introduced into system in the next year run, to provide more power and faster trigger.

4. Optical tweezer:This experiment was triggered by the project of fundamental education improvement funded by the ministry of education. It was developed as a undergraduate teaching experiment in the beginning. We bring it further to a research level. With a more powerful green laser and spatial light modulator, we successfully obtained a micro-particle array (1 micro, 6 particle loop). In this system, the soft matter related problem can be studied, especially, the interaaction between two particales. A new method of correlation analysis has be developed to derive the interaction from.