Applications of 4f and 6f harmonics detection in resolution ofmodulation-broadened spectra,

摘要

Abstract: In this paper, the experiments are carried out by voltage modulating an external-cavity tunable diode laser (TDL). The 2f, 4f and 6f signals of the modulation frequency are measured with cesium D$-2$/ line and the experiment results are compared with theory. Studying results in that there are certain advantages to be gained by going to harmonic- detection greater than usual second (2f) the smaller signal strength at higher harmonics notwithstanding. It is shown that nearly overlapping lines may be better resolved by using 4f and 6f harmonic detection considering the much less modulation-broadened spectra. Results are applicable to trace gas detection using TDLs, and to other areas of spectroscopy and magnetic resonance where harmonic detection techniques are routinely employed to monitor weak signals.!4