© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Control of two-photon absorption by using electromagnetic field in sodium and rubidium vapors

Dong Wang, Jin-Yue Gao, Ji-Hua Xu, Giuseppe Carlo La Rocca, F. Bassani

Published Nov 13, 2001• 0 citations

Abstract

We applied a pumping field to couple the middle level of two- photon absorption with the fourth level. Two-photon absorption minimum was observed. This is the first observation and experimental analysis of such phenomenon after it was predicted four years ago. In sodium vapor, two-photon absorption strength of 3S1/2(Fequals2)-3P3/2-4D3/2 was measured by detecting the fluorescence at 568.3 nm (4D3/2-3P1/2). Levels 3P3/2 and 5S1/2 were connected by pumping field. Experimental data of two-photon absorption strength vs detuning from middle level (TADM) shows that the two-photon absorption was reduced by 60% at line center in the presence of resonant pumping field. In rubidium vapor, two-photon absorption of 5S1/2(Fequals3)-5P3/2-8S1/2(Fequals3) was measured by detecting the fluorescence at 607 nm (8S1/2-5P1/2). Levels 5P3/2 and 5D5/2(Fequals5) were connected by pumping field. The TADM profiles under different experimental condition indicate that the maximum reduction of two-photon absorption can be 80%. And the reduction effect reduced with lower strength, higher detuning frequency and wider line width of pumping field. At the same time, the position of minimum absorption depends on the detuning of pumping field. All the experimental profiles were fitted well with theoretical calculation results.

DOI: 10.1117/12.448258

Related papers

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

Non-contact control of two-photon absorption

Ayan Ray, Waseem Raja, Md.F. Mir +1 more

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.

Applied Optics•Oct 11, 2017•5 citations

Two-photon dichroic atomic vapor laser lock using electromagnetically induced transparency and absorption

F. E. Becerra, R. T. Willis, S. L. Rolston +1 more

We demonstrate a technique to lock the frequency of a laser to a transition between two excited states in Rb vapor using a two-photon process in the presence of a weak magnetic field. We use a ladder configuration from specific hyperfine sublevels of the 5S1/2, 5P3/2, and 5D5/2 levels. This atomic configuration can show electromagnetically induced transparency and absorption processes. The error signal comes from the difference in the transparency or absorption felt by the two orthogonal polarizations of the probe beam. A simplified model is in good quantitative agreement with the observed signals for the experimental parameters. We have used this technique to lock the frequency of the laser up to 1.5 GHz off atomic resonance.

arXiv:0901.2960•Journal of the Optical Society of America B•Jun 10, 2009•26 citations

Determining the Two-Photon Absorption Cross-Section for the 52S1/2 --> 52D5/2 Transition in Naturally Occurring Rubidium

Jeffrey Gallagher, Glen P. Perram

Recently we demonstrated lasing at 420 nm and 455 nm inside of rubidium and cesium vapor cells respectively, by non-resonant, two photon absorption at near infrared pump wavelengths. Two photon absorption from the ground S1/2 state to excited D3/2,5/2 or higher lying S1/2 state via virtual states and subsequent infrared stimulated emission pumps the upper laser levels, the second excited P1/2,3/2 states. To better understand the mechanism and phenomenology of this type of laser, this paper presents a method for determining the two-photon absorption (TPA) cross-section for the 5S1/2 −→ 5D5/2 transition in naturally occurring rubidium. For an incident pump intensity of 392 W cm2 and a rubidium concentration of 3.34 × 10 atoms cm3 , a peak absorbance of 0.10 is observed. The concentration of the Rb in the test cell is determined by one photon absorption spectra of the D2, indicating a vapor curve shifted by 14 C from the exterior wall temperature. The incident laser beam is focused to a waist of 75 μm. The beam quality is consistent with an M = 1.05 − 1.09. A model for the intensity as a function of propagation distance is developed to interpret the observed absorption spectrum and determine a cross-section for the two photon absorption.

AIAA Plasmadynamics and Lasers Conference•Jun 1, 2011•1 citation

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

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

We applied a pumping field to couple the middle level of two- photon absorption with the fourth level. Two-photon absorption minimum was observed. This is the first observation and experimental analysis of such phenomenon after it was predicted four years ago. In sodium vapor, two-photon absorption strength of 3S1/2(Fequals2)-3P3/2-4D3/2 was measured by detecting the fluorescence at 568.3 nm (4D3/2-3P1/2). Levels 3P3/2 and 5S1/2 were connected by pumping field. Experimental data of two-photon absorption strength vs detuning from middle level (TADM) shows that the two-photon absorption was reduced by 60% at line center in the presence of resonant pumping field. In rubidium vapor, two-photon absorption of 5S1/2(Fequals3)-5P3/2-8S1/2(Fequals3) was measured by detecting the fluorescence at 607 nm (8S1/2-5P1/2). Levels 5P3/2 and 5D5/2(Fequals5) were connected by pumping field. The TADM profiles under different experimental condition indicate that the maximum reduction of two-photon absorption can be 80%. And the reduction effect reduced with lower strength, higher detuning frequency and wider line width of pumping field. At the same time, the position of minimum absorption depends on the detuning of pumping field. All the experimental profiles were fitted well with theoretical calculation results.

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.

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.

We demonstrate a technique to lock the frequency of a laser to a transition between two excited states in Rb vapor using a two-photon process in the presence of a weak magnetic field. We use a ladder configuration from specific hyperfine sublevels of the 5S1/2, 5P3/2, and 5D5/2 levels. This atomic configuration can show electromagnetically induced transparency and absorption processes. The error signal comes from the difference in the transparency or absorption felt by the two orthogonal polarizations of the probe beam. A simplified model is in good quantitative agreement with the observed signals for the experimental parameters. We have used this technique to lock the frequency of the laser up to 1.5 GHz off atomic resonance.

Recently we demonstrated lasing at 420 nm and 455 nm inside of rubidium and cesium vapor cells respectively, by non-resonant, two photon absorption at near infrared pump wavelengths. Two photon absorption from the ground S1/2 state to excited D3/2,5/2 or higher lying S1/2 state via virtual states and subsequent infrared stimulated emission pumps the upper laser levels, the second excited P1/2,3/2 states. To better understand the mechanism and phenomenology of this type of laser, this paper presents a method for determining the two-photon absorption (TPA) cross-section for the 5S1/2 −→ 5D5/2 transition in naturally occurring rubidium. For an incident pump intensity of 392 W cm2 and a rubidium concentration of 3.34 × 10 atoms cm3 , a peak absorbance of 0.10 is observed. The concentration of the Rb in the test cell is determined by one photon absorption spectra of the D2, indicating a vapor curve shifted by 14 C from the exterior wall temperature. The incident laser beam is focused to a waist of 75 μm. The beam quality is consistent with an M = 1.05 − 1.09. A model for the intensity as a function of propagation distance is developed to interpret the observed absorption spectrum and determine a cross-section for the two photon absorption.

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.

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.