Interference pulses in optical free induction decay

摘要: A new feature of optical free induction decay (FID) is observed in a coherently prepared sample $^{13}\mathrm{CH}$$_{3}\mathrm{F}$ by the method Stark switching. The preparative phase due to resonant steady-state excitation cw laser beam, and followed FID upon sudden application dc field that switches molecular out resonance. emission not as simple but instead appears train sharp pulses regularly spaced time result repetitive interference. This situation arises because an entire set infrared transitions within split manifold are initially prepared, contrast our previous study nondegenerate transition. emission, which beats with laser, produces heterodyne beat spectrum, consisting frequencies, Fourier transform slowly decaying pulse progression observed. We thus demonstrate what analog well-known NMR high-resolution spectroscopy. detailed behavior agrees well theory assumes be uncoupled. subtle near origin explored also approximate analytic expressions reveal either zero amplitude or sizable depending on degree saturation stage. experimental technique discussed offers attractive way for obtaining spectra without Doppler broadening, generating whose scale can compressed simply increasing field.