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

Applied Optics

Non-contact control of two-photon absorption

Ayan Ray, Waseem Raja, Md.F. Mir, Alok Chakrabarti

Published Oct 11, 2017• 5 citations
Publisher

Abstract

In this experimental work, we address the issue of the control of two-photon absorption in a Doppler broadened medium of Rb85 atoms under the ladder level coupling 5S1/2→5P3/2→5D3/2. Here, suppression and enhancement of two-photon absorption are executed by applying an auxiliary laser beam, which is not physically propagating in the same line of the pump-probe combination. Instead, the auxiliary beam, which is in resonance with the Rb85 D2 transition, is at a finite distance from the line of propagation of the pump-probe combination. The resonant auxiliary beam produces an atomic beam in the vapor cell, and when it reaches the pump-probe path, it creates an asymmetry in the population of ground state hyperfine components. This asymmetry is responsible for controlling two-photon absorption. We present here results obtained by us along with a qualitative explanation of the physical principles behind the control mechanism.

DOI
10.1364/ao.56.008340

Related papers

Observation of an electromagnetically induced change of absorption in multilevel rubidium atoms

Yongqing Li, Shaozheng Jin, Min Xiao

A 64.4% reduction in absorption at the rubidium D2 line is observed when a pumping field at 775.8 nm is tuned on resonance to the transition between the excited states 5${\mathit{P}}_{3/2}$ and 5${\mathit{D}}_{5/2}$. As the pumping field is tuned off resonance, an absorption peak appears at the side of the Doppler-broadened D2 line. This modification in absorption is related to pumping-induced atomic coherence in this three-level ladder-type system. This experiment is done in a Rb vapor cell at room temperature and with cw diode lasers for both pumping and probe beams in a Doppler-free configuration.

Physical Review A•Mar 1, 1995•64 citations

Role of the coupling laser in electromagnetically induced absorption

L. Spani Molella, R.-H. Rinkleff, K. Danzmann

The cesium ${D}_{2}$ line closed hyperfine transition $F=4\ensuremath{\rightarrow}{F}^{\ensuremath{'}}=5$ was simultaneously coupled and probed in a hot atomic beam. We experimentally showed that, when the probe laser frequency approached that of the two-photon-resonance corresponding to electromagnetically induced absorption conditions, an enhanced transparency of the coupling laser appeared, combined with a further central absorption peak at zero probe laser detuning. Simultaneously, the coupling laser parametric dispersion showed a broad negative pattern together with a narrower steep positive phase shift in correspondence with the two-photon resonance, with sub-Doppler half-widths down to about $10\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$.

Physical Review A•Oct 17, 2005•21 citations

Single-Photon-Level Sub-Doppler Pump-Probe Spectroscopy of Rubidium

Paul Burdekin, Samuele Grandi, Rielly Newbold +3 more

We propose and demonstrate pump-probe spectroscopy of rubidium absorption that reveals the sub-Doppler hyperfine structure of the ${}^{5}{\mathrm{S}}_{1/2}\ensuremath{\leftrightarrow}{}^{5}{\mathrm{P}}_{3/2}$ (${\mathrm{D}}_{2}$) transitions. The counterpropagating pump and probe lasers are independently tunable in frequency, with the probe operating at the single-photon level. The two-dimensional spectrum measured as the laser frequencies are scanned shows fluorescence, Doppler-broadened absorption dips, and sub-Doppler features. The detuning between the pump and probe lasers allows compensation of the Doppler shift for all atomic velocities in the room-temperature vapor, meaning we observe sub-Doppler features for all atoms in the beam. We detail a theoretical model of the system that incorporates fluorescence, saturation effects, and optical pumping and compare this with the measured spectrum, finding a mean absolute percentage error of 3.11%. This high level of agreement allows us to extract the number density and temperature of the $\mathrm{Rb}$ vapor from the two-dimensional spectrum. In the future this technique could be used as an atomic frequency standard for calibrating and characterising a single-photon or low-light-level source.

arXiv:2007.08452•Physical Review Applied•Oct 23, 2020•9 citations

Electromagnetically induced two-photon transparency in a four-level system of rubidium atom

Dong Wang, Jin-Yue Gao, Jihua Xu +2 more

An experimental study of electromagnetically induced two- photon transparency (EITT) in rubidium atomic vapor at room temperature is presented. A four level system is considered, involving the two-photon absorption process 5S1/2 to 8S1/2 via an intermediate state 5P3/2, and the single- photon control process 5P3/2 to 5D5/2. A controlling pump laser beam is employed to coherently couple the 5P3/2 and 5D5/2 states, thus producing two dressed intermediate states, which give rise to destructive interference in the two-photon transition. Fluorescence from 8S1/2 to 5P1/2 is used to monitor the 5S1/2(Fequals3) to 8S1/2(Fequals3) two-photon absorption. An induced two-photon transparency of about 80% has been obtained at resonance; the experimental results are in good agreement with the general theory of Agarwal, when the appropriate spectroscopic parameters are employed.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 9, 2001•0 citations

Enhanced absorption in Doppler-free spectroscopy of the Rb atom D 1 line with monochromatic light: Application to laser-frequency stabilization

Peter Yun, Rodolphe Boudot, Qiang Hao +1 more

The detection of narrow and high-amplitude optical resonances in atomic cells is of crucial importance for the development of compact and high-stability lasers or vapor-cell optical references. In this work, using monochromatic light and appropriate polarization settings for the counterpropagating pump and probe beams, we demonstrate the detection of enhanced-absorption sub-Doppler resonances on the ${D}_{1}$ line of the $\mathrm{Rb}$ atom. We report a theoretical model showing that the Zeeman coherence induced between magnetic sublevels---especially in the $F\ensuremath{\rightarrow}{F}^{\ensuremath{'}}=F\ensuremath{-}1$ systems, with $F$ and ${F}^{\ensuremath{'}}$ being the hyperfine quantum numbers of the ground and excited states, respectively---plays a key role in the observed enhanced-absorption process. The theoretically predicted behavior matches the experimental observations well. The impact of light polarization, laser intensity, magnetic field, and cell temperature on the Doppler-free resonance features is experimentally investigated. For application, two identical diode lasers are frequency-stabilized onto enhanced-absorption sub-Doppler resonances. The fractional frequency stability of the laser beatnote is measured to be $1.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$ at $1\phantom{\rule{0.1em}{0ex}}\mathrm{s}$ and $8.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$ at ${10}^{4}\phantom{\rule{0.1em}{0ex}}\mathrm{s}$. These results demonstrate the potential of this scheme for the implementation of a compact or even chip-scale optical frequency reference, which might find applications in instrumentation, navigation, and metrology.

Physical Review Applied•Mar 25, 2025•4 citations

Comparison of absorption, fluorescence, and polarization spectroscopy of atomic rubidium

Seth Ashman, C. Stifler, Joaquín Romero

An ongoing spectroscopic investigation of atomic rubidium utilizes a two-photon, single-laser excitation process. Transitions accessible with our tunable laser include 5P1/2 (F ′ ) ← 5S1/2 (F) and 5P3/2 (F ′ ) ← 5S1/2 (F). The laser is split into a pump and probe beam to allow for Doppler-free measurements of transitions between hyperfine levels. The pump and probe beams are overlapped in a counter-propagating geometry and the laser frequency scans over a transition. Absorption, fluorescence and polarization spectroscopy techniques are applied to this basic experimental setup. The temperature of the vapor cell and the power of the pump and probe beams have been varied to explore line broadening effects and signal-to-noise of each technique. This humble setup will hopefully grow into a more robust experimental arrangement in which double resonance, two-laser excitations are used to explore hyperfine state changing collisions between rubidium atoms and noble gas atoms. Rb-noble gas collisions can transfer population between hyperfine levels, such as 5P3/2 (F ′ = 3) Collision ←− 5P3/2 (F ′ = 2), and the probe beam couples 7S1/2 (F ′′ = 2) ← 5P3/2 (F ′ = 3). Polarization spectroscopy signal depends on the rate of population transfer due to the collision as well as maintaining the orientation created by the pump laser. Fluorescence spectroscopy relies only on transfer of population due to the collision. Comparison of these techniques yields information regarding the change of the magnetic sublevels, mF , during hyperfine state changing collisions.

Bulletin of the American Physical Society•Jun 11, 2015•0 citations
In this experimental work, we address the issue of the control of two-photon absorption in a Doppler broadened medium of Rb85 atoms under the ladder level coupling 5S1/2→5P3/2→5D3/2. Here, suppression and enhancement of two-photon absorption are executed by applying an auxiliary laser beam, which is not physically propagating in the same line of the pump-probe combination. Instead, the auxiliary beam, which is in resonance with the Rb85 D2 transition, is at a finite distance from the line of propagation of the pump-probe combination. The resonant auxiliary beam produces an atomic beam in the vapor cell, and when it reaches the pump-probe path, it creates an asymmetry in the population of ground state hyperfine components. This asymmetry is responsible for controlling two-photon absorption. We present here results obtained by us along with a qualitative explanation of the physical principles behind the control mechanism.
A 64.4% reduction in absorption at the rubidium D2 line is observed when a pumping field at 775.8 nm is tuned on resonance to the transition between the excited states 5P3/2{\mathit{P}}_{3/2}P3/2​ and 5D5/2{\mathit{D}}_{5/2}D5/2​. As the pumping field is tuned off resonance, an absorption peak appears at the side of the Doppler-broadened D2 line. This modification in absorption is related to pumping-induced atomic coherence in this three-level ladder-type system. This experiment is done in a Rb vapor cell at room temperature and with cw diode lasers for both pumping and probe beams in a Doppler-free configuration.
The cesium D2{D}_{2}D2​ line closed hyperfine transition $F=4\ensuremath{\rightarrow}{F}^{\ensuremath{'}}=5$ was simultaneously coupled and probed in a hot atomic beam. We experimentally showed that, when the probe laser frequency approached that of the two-photon-resonance corresponding to electromagnetically induced absorption conditions, an enhanced transparency of the coupling laser appeared, combined with a further central absorption peak at zero probe laser detuning. Simultaneously, the coupling laser parametric dispersion showed a broad negative pattern together with a narrower steep positive phase shift in correspondence with the two-photon resonance, with sub-Doppler half-widths down to about 10kHz10\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}10kHz.
We propose and demonstrate pump-probe spectroscopy of rubidium absorption that reveals the sub-Doppler hyperfine structure of the ${}^{5}{\mathrm{S}}_{1/2}\ensuremath{\leftrightarrow}{}^{5}{\mathrm{P}}_{3/2}$ (D2{\mathrm{D}}_{2}D2​) transitions. The counterpropagating pump and probe lasers are independently tunable in frequency, with the probe operating at the single-photon level. The two-dimensional spectrum measured as the laser frequencies are scanned shows fluorescence, Doppler-broadened absorption dips, and sub-Doppler features. The detuning between the pump and probe lasers allows compensation of the Doppler shift for all atomic velocities in the room-temperature vapor, meaning we observe sub-Doppler features for all atoms in the beam. We detail a theoretical model of the system that incorporates fluorescence, saturation effects, and optical pumping and compare this with the measured spectrum, finding a mean absolute percentage error of 3.11%. This high level of agreement allows us to extract the number density and temperature of the Rb\mathrm{Rb}Rb vapor from the two-dimensional spectrum. In the future this technique could be used as an atomic frequency standard for calibrating and characterising a single-photon or low-light-level source.
An experimental study of electromagnetically induced two- photon transparency (EITT) in rubidium atomic vapor at room temperature is presented. A four level system is considered, involving the two-photon absorption process 5S1/2 to 8S1/2 via an intermediate state 5P3/2, and the single- photon control process 5P3/2 to 5D5/2. A controlling pump laser beam is employed to coherently couple the 5P3/2 and 5D5/2 states, thus producing two dressed intermediate states, which give rise to destructive interference in the two-photon transition. Fluorescence from 8S1/2 to 5P1/2 is used to monitor the 5S1/2(Fequals3) to 8S1/2(Fequals3) two-photon absorption. An induced two-photon transparency of about 80% has been obtained at resonance; the experimental results are in good agreement with the general theory of Agarwal, when the appropriate spectroscopic parameters are employed.
The detection of narrow and high-amplitude optical resonances in atomic cells is of crucial importance for the development of compact and high-stability lasers or vapor-cell optical references. In this work, using monochromatic light and appropriate polarization settings for the counterpropagating pump and probe beams, we demonstrate the detection of enhanced-absorption sub-Doppler resonances on the D1{D}_{1}D1​ line of the Rb\mathrm{Rb}Rb atom. We report a theoretical model showing that the Zeeman coherence induced between magnetic sublevels---especially in the $F\ensuremath{\rightarrow}{F}^{\ensuremath{'}}=F\ensuremath{-}1$ systems, with FFF and ${F}^{\ensuremath{'}}$ being the hyperfine quantum numbers of the ground and excited states, respectively---plays a key role in the observed enhanced-absorption process. The theoretically predicted behavior matches the experimental observations well. The impact of light polarization, laser intensity, magnetic field, and cell temperature on the Doppler-free resonance features is experimentally investigated. For application, two identical diode lasers are frequency-stabilized onto enhanced-absorption sub-Doppler resonances. The fractional frequency stability of the laser beatnote is measured to be $1.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$ at 1s1\phantom{\rule{0.1em}{0ex}}\mathrm{s}1s and $8.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$ at 104s{10}^{4}\phantom{\rule{0.1em}{0ex}}\mathrm{s}104s. These results demonstrate the potential of this scheme for the implementation of a compact or even chip-scale optical frequency reference, which might find applications in instrumentation, navigation, and metrology.
An ongoing spectroscopic investigation of atomic rubidium utilizes a two-photon, single-laser excitation process. Transitions accessible with our tunable laser include 5P1/2 (F ′ ) ← 5S1/2 (F) and 5P3/2 (F ′ ) ← 5S1/2 (F). The laser is split into a pump and probe beam to allow for Doppler-free measurements of transitions between hyperfine levels. The pump and probe beams are overlapped in a counter-propagating geometry and the laser frequency scans over a transition. Absorption, fluorescence and polarization spectroscopy techniques are applied to this basic experimental setup. The temperature of the vapor cell and the power of the pump and probe beams have been varied to explore line broadening effects and signal-to-noise of each technique. This humble setup will hopefully grow into a more robust experimental arrangement in which double resonance, two-laser excitations are used to explore hyperfine state changing collisions between rubidium atoms and noble gas atoms. Rb-noble gas collisions can transfer population between hyperfine levels, such as 5P3/2 (F ′ = 3) Collision ←− 5P3/2 (F ′ = 2), and the probe beam couples 7S1/2 (F ′′ = 2) ← 5P3/2 (F ′ = 3). Polarization spectroscopy signal depends on the rate of population transfer due to the collision as well as maintaining the orientation created by the pump laser. Fluorescence spectroscopy relies only on transfer of population due to the collision. Comparison of these techniques yields information regarding the change of the magnetic sublevels, mF , during hyperfine state changing collisions.