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arXiv · 1310.6465

Frequency Modulation Spectroscopy at High Modulation Depth in an Indium Atomic Beam

Nathan A. Schine·Gambhir Ranjit·Protik K. Majumder
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Abstract

We present a detailed analysis of an application of frequency modulation (FM) spectroscopy in the high modulation depth limit. We have recently completed and reported a measurement of the Stark shift in the indium $5p_{1/2}\rightarrow 6s_{1/2}$ 410 nm transition using this spectroscopy method [Ranjit, et al. Phys. Rev. A 87, 032506 (2013)]. FM spectroscopy proved essential to resolve spectroscopic features in an atomic beam where the optical depth was $\sim 10^{-3}$. A dual-modulation scheme is described which ensures truly background-free FM signals even in the low-density limit. Lock-in detection of the FM signal was accomplished using both the fundamental (1f) and second-harmonic (2f) modulation frequencies. A derivation of both the 1f and 2f signal line shapes in the high-modulation-depth limit is presented. These line shapes form the basis for quantitative fits to a wide variety of experimental FM spectra.

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Nathan A. Schine, Gambhir Ranjit, Protik K. Majumder. 2013-10-24. Frequency Modulation Spectroscopy at High Modulation Depth in an Indium Atomic Beam. https://arxiv.org/abs/1310.6465

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