Molecular laser isotope separation without tunable lasers; Isotope-selective ionization utilizing molecular alignment and angular dependent ionization

波長可変レーザー不要の分子レーザー同位体分離法; 分子整列と角度依存イオン化を利用した同位体選別

赤木 浩; 笠島 辰也*; 熊田 高之   ; 板倉 隆二; 横山 淳; 長谷川 宗良*; 大島 康裕*

Akagi, Hiroshi; Kasajima, Tatsuya*; Kumada, Takayuki; Itakura, Ryuji; Yokoyama, Atsushi; Hasegawa, Hirokazu*; Oshima, Yasuhiro*

We demonstrate nitrogen laser isotope separation without tunable lasers. This method is based on molecular alignment and angular dependent ionization of N and N isotopologues. A linearly-polarized short laser pulse creates rotational wave packets in the two isotopologues, which periodically revive as aligned and anti-aligned distributions with different revival times. Another linearly-polarized short laser pulse at a specific time delay ionizes the aligned isotopologue preferentially because of angular dependence of the ionization probability. As the demonstration, the N and N ion yields were measured as a function of time delay between the alignment and ionization laser pulses. These ion yields show a clear time-delay dependence in the ranges of 0-5 ps and 60-65 ps. The present result indicates that the isotope-selective ionization was realized for the gas mixture without tuning the laser wavelength.