Tunable laser electronic spectroscopy

摘要: The crucial difference between classical and laser spectroscopies is the capability with latter of performing separately usual components a spectroscopic experiment: sample preparation, signal detection, frequency resolution measurement, spectral line assignment. Incompatibilities, such as intensity vs. resolution, are eliminated by this separation. Various experiments will be reviewed illustrations solutions to tactical problems.Excitation spectroscopy separates measurement from thus facilitating recording relatively sparse (<5 lines per cm–1) spectra at limiting precision ( 10–4 far beyond what possible presently available convenient standards. Selective fluorescence detection eliminates “unnecessary” inter-band inter-branch blends simplifies rotational Doppler-width-free techniques, intermodulation optical-optical double resonance (OODR) spectroscopy, provide additional small cost in strength.OODR combines near-perfect prior state selection, ability access “special” levels, strong probe which all prepared molecules participate selectable time, rate on single transition. Optically pumped lasers (OPL) yield information analogous OODR, but one advantage disadvantage. These are, respectively: OPL appears diffraction-limited beam, not over 4π steradians; certain OODR-observable transitions have insufficient gain for oscillation.Spectra acquired tunable ideally suited computer control recording, calibration, assignment processes. All tedious trial-and-error mass data-handling aspects every-experiment-is-a-special-case character high-resolution eliminated.