碘分子双色激光感生光栅光谱

Two-color Laser-induced-grating Spectroscopy of Iodine Molecules

用Ｎｄ：ＹＡＧ激光倍频光分成强度大致相等的两束激光作为泵浦光，以２．７３°交叉于碘分子样品室中，两束泵渝光发生干涉在碘分子中选择激发形成了空间正弦分布的激发态分子光栅和基态耗尽型光栅。另一束窄线宽染料激光作为探索光射入到激光感生光栅上，沿着布拉格衍射的方向接收信号光。扫描探索光的波长，分别在５５５．９～５７０．６ｎｍ，５７６．３～５８７．２ｎｍ和６０５．０～６０５．６ｎｍ的波段内共获得１２９根与碘分子Ｂ－Ｘ态振转能级双共振的双色激光感生光栅光谱谱线。

Two-Color Laser-Induced-Grating Spectroscopy(TC-LIGS)is a newlydeveloped laser spectroscopic technique. This scheme offers the advantages of zerobackground detection,high special resolution and easy spectral edgnment. The secondharmonic output(532 nm)of a Nd:YAG laser is split into two pump beams of nearly equalintensity. These beams intersect at an angle of 2. 73 degree and are directed into theIc sample cell.The interference of these beams preduces a sinusoidal distribution of anexcited-state laser induced population grating and a ground state laser induced depletiongrating in the iodine molecules.A narrow bandwidth dye laser is used as probe beam anddirected to the laser induced gratings.The spectroscopic signal is collected along the directionof Bragg diffraction. By scaning the probe laser wavelength,129 TC-LIG lines coupledbetween B and X states of iodine molecules are obtained in the 555.9-570.6 nm,576.3-587. 2 nm and 605.0-605.6 nm regions.