Japan Atomic Energy Agency (President Yuichi Tonozuka, here after refered as to JAEA) has succeeded to excite cesium atoms to one of two energetically closely-lying states with an unprecedentedly high selectivity and fastness, connecting with a clue to a new method of material control. This work has been done in collaboration with Kyoto University and Institute for Molecular Science.

Recently, the possibility of controlling materials in quantum system is being pursued using the character of waves of materials (wavefunction). This totally new technology is enabled by precisely controlling laser pulse. In the present work, JAEA performed a study of the ultrafast selection of closely-lying states of the cesium atom utilizing the character of the wavefunction of the atom.

With the ordinary light pulse, a precise selection of closely-lying states needs a certain time dependent on the energy separation. In the present study, the laser pulse was sculpted as an "optical key" and interacted with the electron in the atom, inducing the quantum mechanical interference. By controlling the interference, one of two excited states was exclusively formed in a very short period of time. The contrast of the selection ratio exceeds a thousand. The fastness is comparable with the time needed for molecules to change its chemical bond.

After the future development of more sophisticated methods in these technologies, one may freely control chemical reactions and isotope separations which are thought to be hopeless to be realized at this point, and then, contributing to a development of new methods to synthesize chemicals like pharmaceuticals and the atomic energy system which contains safer and less expensive system of the nuclear waste management.

This result was published in Physical Review A: PHYSICAL REVIEW A 72, 063404 (2005).

• Selection of atomic states in a very short time