Double-Resonance Techniques for High-Resolution Raman-Spectroscopy

摘要

In an effort to improve the sensitivity of coherent Raman spectroscopies we have been investigating double-resonance techniques that can combine the high-resolution of stimulated Raman spectroscopy with the sensitivity of electronically resonant spectroscopies such as multiphoton ionization. One such technique that has been highly successful in our laboratory is ionization detected stimulated Raman spectroscopy (IDSRS). In IDSRS, resonant laser ionization is used to detect vibrationally excited molecules produced via stimulated Raman pumping. In a two-step process molecules are first excited to v = 1 levels via a driven stimulated Raman transition. Following this the rotational/vibrational distribution is probed with resonant laser ionization by a tunable UV source. Raman spectra are then obtained by scanning the frequency of one of the Raman pump sources and monitoring the ionziation signal as a function of the frequency difference (Stokes shift) between this laser and the second, fixed-frequency, visible pump laser. 4 refs., 1 fig. (ERA citation 11:041142)