Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Optoelectronics·laser

Measurement of Modulation Index with High-order-harmonic Detection

Yin Wang

Published Jan 1, 2002• 0 citations
OpenAlex

Abstract

The modulation indexes have been measured by the harmonics intensity ratios (4f max /6f max ).By use of the numerical analysis,we get the relationship of the modulation index and high harmonics (4f,6f) detection.We also get 4f and 6f harmonic signals about the 6S 1/2 (F=4)→6P 3/2 transition of the cesium D 2 line using the voltage modulation.The experimental results are fairly agreement with theoretical analysis.This method is efficient for the measurements of the modulation depth and line width.

Related papers

High-resolution Reflection Spectroscopy ofCs D_2 Line Studied byHigh-order-harmonic Detection

Jia Suo-Tang

In this paper, by numerical analysis the relationship of the modulation broaden index with modulation index using high-order-harmonic detection is investigated. Using the voltage modulation the 2f,4f and 6f harmonic signals about the reflection spectroscopy of 6S1/2(F = 4) →6P3/2 transition of the cesium D2 line are also be measured. The experimental results are in good agreement with the theoretical predictions. It is found that narrower line-width can be achieved by higher-harmonic detection than the line-width detected by direct absorption when the modulation index is smaller than 1.81, 2.98 and 4.14 for 2f, 4f, and 6f signals, respectively.

中国激光(英文版)•Jan 1, 2002•0 citations

Measurement of the wavelength modulation indices with selective reflection spectroscopy

Liantuan Xiao, Jianming Zhao, Wangbao Yin +4 more

The wavelength modulation indices are measured based on harmonic amplitude ratio of 4f_(amp)/6f_(amp) (4f_(amp) and 6f_(amp) are the 4- and 6-th harmonic central peak amplitudes correspondingly) with the Doppler-free selective reflection modulation spectroscopy. The experiments for the 6S_(1/2)(F = 4) ? 6P_(3/2)(F' = 5) transition of cesium D_(2) line with 30-MHz linewidth were carried out. The 4f- and 6f-harmonic signals were detected with two digital lock-in amplifiers separately. The maximum error for modulation indices measurement was ±0.1 within the range of m from 3 to 6. The non-linear modulation behaviour of an external cavity diode laser induced by voltage tuning was studied with this method. The method for modulation indices measurement does not require a solid etalon as usual for measuring the wavelength modulation depth and the absorption linewidth correspondingly.

Chinese Optics Letters•Jan 1, 2003•2 citations

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

Nathan Schine, Gambhir Ranjit, Protik Majumder

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.

arXiv:1310.6465•Oct 24, 2013•0 citations

The Transmission Spectrum in a Thin Cs Vapor Cell

Jia Suo-Tang

The single light beam transmission spectrum of the 6S 1/2 →6P 3/2  in a thin (about 150 μm) vapor cell of the cesium atom is measured with freque n cy modulation technology. The high harmonics of the signal are measured correspo ndingly. The spectrum reveals sub-Doppler features. And the effect of the laser power on the signal is investigated.

Acta Sinica Quantum Optica•Jan 1, 2003•0 citations

Large optical depth frequency modulation spectroscopy

Chang Chi Kwong, E. A. Chan, S. A. Aljunid +2 more

Band-resolved frequency modulation spectroscopy is a common method to measure weak signals of radiative ensembles. When the optical depth of the medium is large, the signal drops exponentially and the technique becomes ineffective. In this situation, we show that a signal can be recovered when a larger modulation index is applied. Noticeably, this signal can be dominated by the natural linewidth of the resonance, regardless of the presence of inhomogeneous line broadening. We implement this technique on a cesium vapor, and then explore its main spectroscopic features. This work opens the road towards measurement of cooperative emission effects in bulk atomic ensemble.

arXiv:1902.06926•Optics Express•Oct 23, 2019•3 citations

Experimental investigation of the sub-Doppler transmission spectroscopy in a thin vapour layer at room temperature

Yanting Zhao, Jianming Zhao, Huang Tao +2 more

The sub-Doppler transmission spectrum in a thin vapour layer (about 150 μm) was observed at room temperature using the wavelength modulation technology. The absorption signal and its second-order harmonic were detected with an external-cavity diode laser. A sub-Doppler spectrum corresponding to resonant transitions of the caesium D 2 line (6S 1/2 →6P 3/2 ) was demonstrated. The dependence of the transmission signal on the intensity of the laser was also investigated.

Chinese Physics•Sep 1, 2004•0 citations
The modulation indexes have been measured by the harmonics intensity ratios (4f max /6f max ).By use of the numerical analysis,we get the relationship of the modulation index and high harmonics (4f,6f) detection.We also get 4f and 6f harmonic signals about the 6S 1/2 (F=4)→6P 3/2 transition of the cesium D 2 line using the voltage modulation.The experimental results are fairly agreement with theoretical analysis.This method is efficient for the measurements of the modulation depth and line width.
In this paper, by numerical analysis the relationship of the modulation broaden index with modulation index using high-order-harmonic detection is investigated. Using the voltage modulation the 2f,4f and 6f harmonic signals about the reflection spectroscopy of 6S1/2(F = 4) →6P3/2 transition of the cesium D2 line are also be measured. The experimental results are in good agreement with the theoretical predictions. It is found that narrower line-width can be achieved by higher-harmonic detection than the line-width detected by direct absorption when the modulation index is smaller than 1.81, 2.98 and 4.14 for 2f, 4f, and 6f signals, respectively.
The wavelength modulation indices are measured based on harmonic amplitude ratio of 4f_(amp)/6f_(amp) (4f_(amp) and 6f_(amp) are the 4- and 6-th harmonic central peak amplitudes correspondingly) with the Doppler-free selective reflection modulation spectroscopy. The experiments for the 6S_(1/2)(F = 4) ? 6P_(3/2)(F' = 5) transition of cesium D_(2) line with 30-MHz linewidth were carried out. The 4f- and 6f-harmonic signals were detected with two digital lock-in amplifiers separately. The maximum error for modulation indices measurement was ±0.1 within the range of m from 3 to 6. The non-linear modulation behaviour of an external cavity diode laser induced by voltage tuning was studied with this method. The method for modulation indices measurement does not require a solid etalon as usual for measuring the wavelength modulation depth and the absorption linewidth correspondingly.
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→6s1/25p_{1/2}\rightarrow 6s_{1/2}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\sim 10^{-3}∼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.
Band-resolved frequency modulation spectroscopy is a common method to measure weak signals of radiative ensembles. When the optical depth of the medium is large, the signal drops exponentially and the technique becomes ineffective. In this situation, we show that a signal can be recovered when a larger modulation index is applied. Noticeably, this signal can be dominated by the natural linewidth of the resonance, regardless of the presence of inhomogeneous line broadening. We implement this technique on a cesium vapor, and then explore its main spectroscopic features. This work opens the road towards measurement of cooperative emission effects in bulk atomic ensemble.