光泵分子气体远红外光谱的AC Stark效应

本文应用图论法研究光泵激光气体分子的波谱特性。假定了:1.分子与外来信号场相互作用输运过程中只涉及到六个能级;2.泵场强远大于探测场强。在这些假定下求解密度矩阵方程,获得一套反映受激分子波谱特性的解析表达式。应用这些表达式,可求得不同频率的泵场作用下分子气体的远红外波谱特性。本文特别叙述分子振动基态远红外光谱的AC aStark效应。结果表明:在谐振点AC aStark分裂的值与C.H.Townes所得结果基本相同,在受激发射和吸收共存的情况下,特性曲线的总趋向与他的结果基本一致。调谐曲线有些部份反映发射特性,有些部份反映吸收特性,在发射和吸收的过渡部份,吸收和发射都很小,而且具有特殊的过渡特性。

AC Stark Effect of FIR Spectrum of Vibrational Ground State of Optically Pumped Gas Molecules

The FIR spectrum of optically Pumped gaseous molecules was studied theoretically. The signal flow graph was used to solve the density matrix equations of the system assuming that. 1) the molecule interacting with the incident signal (including the pump and detecting signal) was considered to be a six-level quantum system; 2) the pumping power was much larger than the FIR probing signal. A set of analytical solution of the spectral characteristics of-the activated molecules has been obtained. The AC Stark effect of the FIR spectrum of vibrational ground state of activated molecules was demonstrated.The theoretical AC Stark splittings of both the laser lines and absorption spectral lines were in good agreement with the result obtained by C.H.Townes in 1955. A special transition between absorption and emission parts of the characteristic curve was found. The value of AC Stark splitting equals 2Bp/n,where n is the number of FIR photon in the multiphoton process.