We report a three-photon resonant six-wave mixing (SWM) with phase- conjugation geometry. It has advantages that phase matching condition is not critical and the generation of SWM signal is efficient. This technique p...We report a three-photon resonant six-wave mixing (SWM) with phase- conjugation geometry. It has advantages that phase matching condition is not critical and the generation of SWM signal is efficient. This technique provides a new spectroscopic tool for studying the highly excited atomic or molecular states with high resolution. The feasibility of this technique is demonstrated in sodium vapour.展开更多
Quantum interference may lead to suppression and enhancement of the two-photon resonant nondegenerate fourwave mixing signal in a cascade four-level system.Such phenomena are demonstrated in Ba through inducing atomic...Quantum interference may lead to suppression and enhancement of the two-photon resonant nondegenerate fourwave mixing signal in a cascade four-level system.Such phenomena are demonstrated in Ba through inducing atomic coherence between the ground state 6s^2 and the doubly excited autoionizing Rydberg state 6trod.This method can be used as a new spectroscopic tool for measuring the transition dipole moment between two highly excited atomic states.展开更多
An Autler-Townes(AT) spectroscopy based on phase conjugate six-wave mixing(SWM) is proposed to detect AT doublet of high-lying state in a Doppler-broadened cascade four-level system.It is found that the SWM spectrum i...An Autler-Townes(AT) spectroscopy based on phase conjugate six-wave mixing(SWM) is proposed to detect AT doublet of high-lying state in a Doppler-broadened cascade four-level system.It is found that the SWM spectrum is dependent strongly on the ratios between the magnitudes of the wave vectors.We discuss how the Doppler broadening affects the SWM spectrum from a time-domain viewpoint and find that,due the atomic motion,the atomic polarizations acquire different phases for atoms with different velocities as time evolves.The Doppler free SWM spectrum can be obtained only when the atomic polarization can be rephasing again at certain time after the interactions of all the incident fields.展开更多
^(40)K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low concentration(0.012%) of ^(40)K in natural abundance of potassium, most experiments use 4–10% enriched potass...^(40)K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low concentration(0.012%) of ^(40)K in natural abundance of potassium, most experiments use 4–10% enriched potassium source, which have greatly suffered from the extremely low annual production and significant price hikes in recent years. Using naturally abundant potassium source, we capture 5.4 × 10~6 cold ^(40)K atoms with the help of a high performance of two-dimensional magneto-optical trap(2D^+MOT), which is almost three orders of magnitude greater than previous results without the 2D^+ MOT. The number of the ^(40)K atoms is sufficient for most ultra-cold ^(40)K experiments, and our approach provides an ideal alternative for the field.展开更多
We measure the absorption and dispersion in a Doppler-broadened Λ-type three level system by resonant stimulated Raman spectroscopy with homodyne detection. Through studying the dressed state energies of the system, ...We measure the absorption and dispersion in a Doppler-broadened Λ-type three level system by resonant stimulated Raman spectroscopy with homodyne detection. Through studying the dressed state energies of the system, it is found that the absorption and dispersion satisfy the Kramers–Kronig relation. The absorption and dispersion spectra calculated by employing this relation agree well with our experimental observations.展开更多
We study the relationship between electromagnetically-induced transparency(EIT) and Autler–Townes(AT) splitting in a cascade three-level Doppler-broadened system. By comparing the absorption spectrum with the fluores...We study the relationship between electromagnetically-induced transparency(EIT) and Autler–Townes(AT) splitting in a cascade three-level Doppler-broadened system. By comparing the absorption spectrum with the fluorescence excitation spectrum, it is found that for a Doppler-broadened system, EIT resonance cannot be explained as the result of quantum interference, unlike the case of a homogeneously broadened system. Instead, the macroscopic polarization interference plays an important role in determining the spectra of EIT and AT splitting, which can be explained within the same framework when being detected by the absorption spectra.展开更多
We study the electromagnetically-induced transparency(EIT)in a Doppler-broadened cascaded three-level system.We decompose the susceptibility responsible for the EIT resonance into a linear and a nonlinear part,and the...We study the electromagnetically-induced transparency(EIT)in a Doppler-broadened cascaded three-level system.We decompose the susceptibility responsible for the EIT resonance into a linear and a nonlinear part,and the EIT resonance reflects mainly the characteristics of the nonlinear susceptibility.It is found that the macroscopic polarization interference effect plays a crucial role in determining the EIT resonance spectrum.To obtain a Doppler-free spectrum there must be polarization interference between atoms of different velocities.A dressed-state model,which analyzes the velocities at which the atoms are in resonance with the dressed states through Doppler frequency shifting,is employed to explain the results.展开更多
Based on Akaike's information criterion(AIC) for a coherently driven ensemble of cold rubidium atoms, we study the crossover between electromagnetically induced transparency(EIT) and Autler–Townes(AT) splitting f...Based on Akaike's information criterion(AIC) for a coherently driven ensemble of cold rubidium atoms, we study the crossover between electromagnetically induced transparency(EIT) and Autler–Townes(AT) splitting from the dispersion as well as the absorption viewpoint. We find that the dispersion signal is more sensitive than the absorption signal, showing more pronounced features in the Akaike per-point weights spectrum, which provides a cleaner way of discerning EIT from AT splitting.展开更多
基金Project supported by the National Natural Science foundation of China （Grant Nos 10174096 and 10374113） and the National Program for Basic Research in China （Grant No 001CB309301）.
文摘We report a three-photon resonant six-wave mixing (SWM) with phase- conjugation geometry. It has advantages that phase matching condition is not critical and the generation of SWM signal is efficient. This technique provides a new spectroscopic tool for studying the highly excited atomic or molecular states with high resolution. The feasibility of this technique is demonstrated in sodium vapour.
文摘Quantum interference may lead to suppression and enhancement of the two-photon resonant nondegenerate fourwave mixing signal in a cascade four-level system.Such phenomena are demonstrated in Ba through inducing atomic coherence between the ground state 6s^2 and the doubly excited autoionizing Rydberg state 6trod.This method can be used as a new spectroscopic tool for measuring the transition dipole moment between two highly excited atomic states.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB922002)the National Natural Science Foundation of China(Grant Nos.11274376 and 61308011)the National High Technology Research and Development Program of China(Grant No.2011AA120102)
文摘An Autler-Townes(AT) spectroscopy based on phase conjugate six-wave mixing(SWM) is proposed to detect AT doublet of high-lying state in a Doppler-broadened cascade four-level system.It is found that the SWM spectrum is dependent strongly on the ratios between the magnitudes of the wave vectors.We discuss how the Doppler broadening affects the SWM spectrum from a time-domain viewpoint and find that,due the atomic motion,the atomic polarizations acquire different phases for atoms with different velocities as time evolves.The Doppler free SWM spectrum can be obtained only when the atomic polarization can be rephasing again at certain time after the interactions of all the incident fields.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0300600 and2016YFA0301500the National Natural Science Foundation of China under Grant Nos 11474347,61227902 and 61775232
文摘^(40)K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low concentration(0.012%) of ^(40)K in natural abundance of potassium, most experiments use 4–10% enriched potassium source, which have greatly suffered from the extremely low annual production and significant price hikes in recent years. Using naturally abundant potassium source, we capture 5.4 × 10~6 cold ^(40)K atoms with the help of a high performance of two-dimensional magneto-optical trap(2D^+MOT), which is almost three orders of magnitude greater than previous results without the 2D^+ MOT. The number of the ^(40)K atoms is sufficient for most ultra-cold ^(40)K experiments, and our approach provides an ideal alternative for the field.
基金supported by the National Basic Research Program of China(Grant Nos.2013CB922002 and 2010CB922904)the National Natural Science Foundation of China(Grant Nos.11274376 and 61308011)the Natural Science Foundation of Hebei Province,China(Grant No.A2015205161)
文摘We measure the absorption and dispersion in a Doppler-broadened Λ-type three level system by resonant stimulated Raman spectroscopy with homodyne detection. Through studying the dressed state energies of the system, it is found that the absorption and dispersion satisfy the Kramers–Kronig relation. The absorption and dispersion spectra calculated by employing this relation agree well with our experimental observations.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11404330,11274376,61308011,and 11474347)the NSAF,China(Grant No.U1330117)+1 种基金the National Basic Research Program of China(Grant Nos.2013CB922002 and 2010CB922904)the China Postdoctoral Science Foundation(Grant No.119103S239)
文摘We study the relationship between electromagnetically-induced transparency(EIT) and Autler–Townes(AT) splitting in a cascade three-level Doppler-broadened system. By comparing the absorption spectrum with the fluorescence excitation spectrum, it is found that for a Doppler-broadened system, EIT resonance cannot be explained as the result of quantum interference, unlike the case of a homogeneously broadened system. Instead, the macroscopic polarization interference plays an important role in determining the spectra of EIT and AT splitting, which can be explained within the same framework when being detected by the absorption spectra.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10974252,11274376,60978002,and 11179041)the National Basic Research Program of China(Grant No.2010CB922904)+2 种基金the National High Technology Research and Development Program of China(Grant No.2011AA120102)the Natural Science Foundation of Inner Mongolia,China(Grants No.2012MS0101)the Innovation Fund of Inner Mongolia University of Science and Technology,China(Grants No.2010NC064)
文摘We study the electromagnetically-induced transparency(EIT)in a Doppler-broadened cascaded three-level system.We decompose the susceptibility responsible for the EIT resonance into a linear and a nonlinear part,and the EIT resonance reflects mainly the characteristics of the nonlinear susceptibility.It is found that the macroscopic polarization interference effect plays a crucial role in determining the EIT resonance spectrum.To obtain a Doppler-free spectrum there must be polarization interference between atoms of different velocities.A dressed-state model,which analyzes the velocities at which the atoms are in resonance with the dressed states through Doppler frequency shifting,is employed to explain the results.
基金Project supported by the National Basic Research Program of China(Grant Nos.2013CB922002 and 2010CB922904)the National Natural Science Foundation of China(Grant Nos.11274376,61308011,and 11474347)
文摘Based on Akaike's information criterion(AIC) for a coherently driven ensemble of cold rubidium atoms, we study the crossover between electromagnetically induced transparency(EIT) and Autler–Townes(AT) splitting from the dispersion as well as the absorption viewpoint. We find that the dispersion signal is more sensitive than the absorption signal, showing more pronounced features in the Akaike per-point weights spectrum, which provides a cleaner way of discerning EIT from AT splitting.
