Detection of saturated absorption spectroscopy at high sensitivity with displaced crossovers

We discuss a refined, hybrid rf/optical technique for studying sub-Doppler saturated absorption/dispersion resonances with excellent precision and symmetry. Sensitivity is limited mainly by fundamental noise in the signal. Resonance profiles obtained in I2 are in remarkable agreement with theory. The method promises a new level of accuracy for laser locking to an optical resonance.

Applied Physics LettersNov 1, 1981331 citations

Hyperfine spectroscopy using co-propagating pump-probe beams

Alok K. Singh, Sapam Ranjita Chanu, Dipankar Kaundilya +1 more

arXiv:1008.5292Aug 31, 20100 citations

Detection of saturated absorption spectroscopy at high sensitivity with displaced crossovers

Jun Duan, Xianghui Qi, Xiaoji Zhou, Xuzong Chen

Published Jan 1, 2011• 6 citations

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Abstract

Related papers

Detection of saturated absorption spectroscopy at high sensitivity with displaced crossovers

Jun Duan, Xianghui Qi, Xiaoji Zhou +1 more

We present an unconventional experimental approach for detecting saturated absorption spectroscopy. Using this approach, crossover peaks are displaced, leaving out peaks corresponding to an atom's natural resonant frequencies. Sensitivity of detection can also be enhanced. Consequently, the spectrum could reflect the energy structure of atoms more explicitly. Without harmful influence from crossovers, the locking range of the error signal is significantly increased and the symmetry of the dispersion line shape is perfectly preserved, so reliability of frequency stabilization can be improved.We present an unconventional experimental approach for detecting saturated absorption spectroscopy. Using this approach, crossover peaks are displaced, leaving out peaks corresponding to an atom's natural resonant frequencies. Sensitivity of detection can also be enhanced. Consequently, the spectrum could reflect the energy structure of atoms more explicitly. Without harmful influence from crossovers, the locking range of the error signal is significantly increased and the symmetry of the dispersion line shape is perfectly preserved, so reliability of frequency stabilization can be improved.

arXiv:1011.5145Optics LettersFeb 11, 20118 citations

Saturated-absorption spectroscopy: eliminating crossover resonances by use of copropagating beams

Ayan Banerjee, Vasant Natarajan A

We demonstrate a new technique for saturated-absorption spectroscopy by use of copropagating beams that does not have the problem of crossover resonances. The pump beam is locked to a transition, and its absorption signal is monitored while the probe beam is scanned. As the probe comes into resonance with another transition, the pump absorption is reduced and the signal shows a Doppler-free dip. We use this technique to measure hyperfine intervals in the D2 line of 85Rb with a precision of 70 kHz and to resolve hyperfine levels in the D2 line of 39K that are less than 10 MHz apart.We demonstrate a new technique for saturated-absorption spectroscopy by use of copropagating beams that does not have the problem of crossover resonances. The pump beam is locked to a transition, and its absorption signal is monitored while the probe beam is scanned. As the probe comes into resonance with another transition, the pump absorption is reduced and the signal shows a Doppler-free dip. We use this technique to measure hyperfine intervals in the D2 line of 85Rb with a precision of 70 kHz and to resolve hyperfine levels in the D2 line of 39K that are less than 10 MHz apart.

arXiv:physics/0307095Optics LettersOct 15, 200358 citations

Laser frequency stabilization using bichromatic crossover spectroscopy

Taek Jeong, Han Seb Moon

We propose a Doppler-free spectroscopic method named bichromatic crossover spectroscopy (BCS), which we then use for the frequency stabilization of an off-resonant frequency that does not correspond to an atomic transition. The observed BCS in the 5S1/2 → 5P1/2 transition of 87Rb is related to the hyperfine structure of the conventional saturated absorption spectrum of this transition. Furthermore, the Doppler-free BCS is numerically calculated by considering all of the degenerate magnetic sublevels of the 5S1/2 → 5P1/2 transition in an atomic vapor cell, and is found to be in good agreement with the experimental results. Finally, we successfully achieve modulation-free off-resonant locking at the center frequency between the two 5S1/2(F = 1 and 2) → 5P1/2(F′ = 1) transitions using a polarization rotation of the BCS. The laser frequency stability was estimated to be the Allan variance of 2.1 × 10−10 at 1 s.We propose a Doppler-free spectroscopic method named bichromatic crossover spectroscopy (BCS), which we then use for the frequency stabilization of an off-resonant frequency that does not correspond to an atomic transition. The observed BCS in the 5S1/2 → 5P1/2 transition of 87Rb is related to the hyperfine structure of the conventional saturated absorption spectrum of this transition. Furthermore, the Doppler-free BCS is numerically calculated by considering all of the degenerate magnetic sublevels of the 5S1/2 → 5P1/2 transition in an atomic vapor cell, and is found to be in good agreement with the experimental results. Finally, we successfully achieve modulation-free off-resonant locking at the center frequency between the two 5S1/2(F = 1 and 2) → 5P1/2(F′ = 1) transitions using a polarization rotation of the BCS. The laser frequency stability was estimated to be the Allan variance of 2.1 × 10−10 at 1 s.

Journal of Applied PhysicsMar 3, 20155 citations

Saturated absorption spectroscopy with a Zeeman shift

Un Yob Shim, Jong-An Kim, W. Jhe

Recently a new type of spectroscopy using Zeeman shift has been developed, which aims for a large recapture range by making a dispersive-like signal obtained from the subtraction of two different circularly polarized Doppler-broadened absorption signals in the presence of a magnetic field (order of 100 G). We would like to propose another method for stabilizing a diode laser frequency onto an atomic frequency with a small tunable range in the presence of small longitudinal magnetic field (order of Gauss). A solid state diode laser is preferred as it is a good light source. Our technique has the advantages of cancellation of frequency fluctuation over side-locking and no need for phase-sensitive detection and frequency modulation over peak-locking. A subtracted SAS signal and the blocking signal are displayed on one photodiode.Recently a new type of spectroscopy using Zeeman shift has been developed, which aims for a large recapture range by making a dispersive-like signal obtained from the subtraction of two different circularly polarized Doppler-broadened absorption signals in the presence of a magnetic field (order of 100 G). We would like to propose another method for stabilizing a diode laser frequency onto an atomic frequency with a small tunable range in the presence of small longitudinal magnetic field (order of Gauss). A solid state diode laser is preferred as it is a good light source. Our technique has the advantages of cancellation of frequency fluctuation over side-locking and no need for phase-sensitive detection and frequency modulation over peak-locking. A subtracted SAS signal and the blocking signal are displayed on one photodiode.

Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR)Jan 20, 20030 citations

Optical heterodyne saturation spectroscopy

J. L. Hall, Leo W. Hollberg, T. Baer +1 more

Applied Physics LettersNov 1, 1981331 citations

Hyperfine spectroscopy using co-propagating pump-probe beams

Alok K. Singh, Sapam Ranjita Chanu, Dipankar Kaundilya +1 more

We have shown earlier that hyperfine spectroscopy in a vapor cell using co-propagating pump-probe beams has many advantages over the usual technique of saturated-absorption spectroscopy using counter-propagating beams. The main advantages are the absence of crossover resonances, the appearance of the signal on a flat (Doppler-free) background, and the higher signal-to-noise ratio of the primary peaks. Interaction with non-zero-velocity atoms causes additional peaks, but only one of them appears within the primary spectrum. We first illustrate the advantages of this technique for high-resolution spectroscopy by studying the $D_2$ line of Rb. We then use an acousto-optic modulator (AOM) for frequency calibration to make precise hyperfine-interval measurements in the first excited $P_{3/2}$ state of $^{85,87}$ Rb and $^{133}$ Cs.We have shown earlier that hyperfine spectroscopy in a vapor cell using co-propagating pump-probe beams has many advantages over the usual technique of saturated-absorption spectroscopy using counter-propagating beams. The main advantages are the absence of crossover resonances, the appearance of the signal on a flat (Doppler-free) background, and the higher signal-to-noise ratio of the primary peaks. Interaction with non-zero-velocity atoms causes additional peaks, but only one of them appears within the primary spectrum. We first illustrate the advantages of this technique for high-resolution spectroscopy by studying the $D_2$ line of Rb. We then use an acousto-optic modulator (AOM) for frequency calibration to make precise hyperfine-interval measurements in the first excited $P_{3/2}$ state of $^{85,87}$Rb and $^{133}$Cs.

arXiv:1008.5292Aug 31, 20100 citations

D_2

line of Rb. We then use an acousto-optic modulator (AOM) for frequency calibration to make precise hyperfine-interval measurements in the first excited

P_{3/2}

state of

^{85,87}

Rb and

^{133}

Cs.