2013/10/24 by Nathan A. Schine, Nathan Schine, Gambhir Ranjit +5
Engineering · Physics and Astronomy · #Atomic Physics (physics.atom-ph) #FOS: Physical sciences #Quantum optics and atomic interactions #Radiation Detection and Scintillator Technologies #Terahertz technology and applications #physics.atom-ph
paper · pdf · doi:10.48550/arxiv.1310.6465
13 pages, 8 figures
arxiv created 2013/10/24 · openalex publication_date 2013/10/24 · arxiv updated 2013/10/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 5p1/2→ 6s1/2 410 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 ∼ 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.