The quantum noise of squeezed probe light passing through an atomic system with different electromagnetically induced transparency and AutlewTownes splitting effects is investigated theoretically. It is found that the...The quantum noise of squeezed probe light passing through an atomic system with different electromagnetically induced transparency and AutlewTownes splitting effects is investigated theoretically. It is found that the optimal squeezing preservation of the outgoing probe beam occurs in the strong-coupling-field regime rather than in the weak- coupling-field regime. In the weak-coupling-field regime, which was recently recognized as the electromagnetically induced transparency regime （Abi-Salloum T Y 2010 Phys. Rev. A 81 053836）, the output amplitude noise is affected mainly by the atomic noise originating from the random decay process of atoms. While in the strong-coupling-field regime, defined as the Autler-Townes splitting regime, the output amplitude noise is affected mainly by the phase-to- amplitude conversion noise. This is useful in improving the quality of the experiment for efficient quantum memory, and hence has an application in quantum information processing.展开更多
We would like to point out the misprinted Fig.3 in our published paper[Chin.Phys.B 32,114205(2023)].Since only orders of subfigures need to be corrected and the main results of the published paper are correct,we prese...We would like to point out the misprinted Fig.3 in our published paper[Chin.Phys.B 32,114205(2023)].Since only orders of subfigures need to be corrected and the main results of the published paper are correct,we present the correct figure in this corrigendum.展开更多
We analytically and numerically investigate a signal light storing mechanism based on the controllable electromagnetically induced transparency(EIT)effect.We demonstrate that the isolation between the waveguide and th...We analytically and numerically investigate a signal light storing mechanism based on the controllable electromagnetically induced transparency(EIT)effect.We demonstrate that the isolation between the waveguide and the cavities cannot be achieved instantly as soon as the two cavities are tuned into resonance,no matter the index tuning rate is ultrafast or slow.We also investigate the temporal evolution features of the intracavity energy when the pulse during time is prolonged.We find many periodical oscillations of the trapped energy in both cavities,and they are entirely complementary.Our analysis shows that the adiabatic wavelength conversion in both cavities and a phase difference π between them play critical roles in this phenomenon.展开更多
In recent years, most studies have focused on the perfect absorption and high-efficiency quantum memory of the onesided system, ignoring the characteristics of its optical switching contrast. Thus, the performance of ...In recent years, most studies have focused on the perfect absorption and high-efficiency quantum memory of the onesided system, ignoring the characteristics of its optical switching contrast. Thus, the performance of all-optical switching and optical transistors is limited. Herein, we propose a localized surface plasmon(LSP) mode-assisted cavity QED system which consists of a Λ-shaped three-level quantum emitter(QE), a metal nanoparticle and a one-sided optical cavity with a fully reflected mirror. In this system, the QE coherently couples to the cavity and LSP mode respectively, which is manipulated by the control field. As a result, considerably high and stable switch contrast of 90% can be achievable due to the strong confined field of the LSP mode and perfect absorption of the optical medium. In addition, we obtain a power dependent effect between the control field and the transmitted frequency as a result of the converted dark state. We employ the Heisenberg–Langevin equation and numerical master equation formalisms to explain high switching, controllable output light and the dark state. Our system introduces an effective method to improve the performance of optical switches based on the one-sided system in quantum information storage and quantum communication.展开更多
We demonstrate a simple method to measure electric field intensity by using doublet electromagnetically induced transparency(EIT) spectra of cold Rb Rydberg atoms, where the frequency of the coupling laser does not ne...We demonstrate a simple method to measure electric field intensity by using doublet electromagnetically induced transparency(EIT) spectra of cold Rb Rydberg atoms, where the frequency of the coupling laser does not need to be locked. Based on the Stark splitting of the Rb Rydberg state, 10D_(3/2), under electric fields and the corresponding calculated polarizabilities, the real electric field intensity is calculated using the difference in radio-frequency diffraction between two acousto-optic modulators, which acts as a frequency criterion that allows us to measure the electrical field without locking the coupling laser. The value measured by this simple method shows a good agreement with our previous work [Opt.Express 29 1558(2021)] where the frequency of the coupling laser needs to be locked with an additional EIT spectrum based on atom vapor and a proportional–integral–differential feedback circuit. Our presented method can also be extended to the measurement of electric field based on hot Rydberg atom vapor, which has application in industry.展开更多
We report on electromagnetically induced transparency cooling of ^(40)Ca^(+)to sympathetically cool the threedimensional secular modes of motion in a ^(40)Ca^(+)–^(27)Al^(+)two-ion pair near the ground state.We obser...We report on electromagnetically induced transparency cooling of ^(40)Ca^(+)to sympathetically cool the threedimensional secular modes of motion in a ^(40)Ca^(+)–^(27)Al^(+)two-ion pair near the ground state.We observe simultaneous ground state cooling across all radial modes and axial modes of a ^(40)Ca^(+)–^(27)Al^(+)ion pair,occupying a broader cooling range in frequency space over 3 MHz.The cooling time is observed to be less than 1 ms.The mean phonon number and heating rates of all motional modes are measured.This study is not only an important step for reducing the secular motion time-dilation shift uncertainty and uptime ratio of ^(27)Al^(+)optical clock,but also essential for high-fidelity quantum simulations and quantum information processors using trapped ions.展开更多
Optical nanofiber(ONF) is a special tool for effectively controlling coupling of light and atoms. In this paper, we study the ladder-type electromagnetically induced transparent(EIT) under ultralow power level in a wa...Optical nanofiber(ONF) is a special tool for effectively controlling coupling of light and atoms. In this paper, we study the ladder-type electromagnetically induced transparent(EIT) under ultralow power level in a warm cesium vapor by observing the transmission of ONF that couples the 6 S → 6 P Cs atoms in the presence of a 6 P → 8 S control beam through the same fiber. The linewidth and transmission of the EIT signal are investigated at different intensities of the control laser. In addition, we theoretically study the nonlinear interaction at the ONF interface using the multi-level density matrix equations, and obtain good agreements between theory and experiments. The results may have great significance for further study of optical nonlinear effect at low power level.展开更多
A graphene-based metamaterial with tunable electromagnetically induced transparency （EIT）-like transmission is nu- merically studied in this paper. The proposed structure consists of a graphene layer composed of cou...A graphene-based metamaterial with tunable electromagnetically induced transparency （EIT）-like transmission is nu- merically studied in this paper. The proposed structure consists of a graphene layer composed of coupled cut-wire pairs printed on a substrate. The simulation confirms that an EIT-like transparency window can be observed due to indirect cou- pling in a terahertz frequency range. More importantly, the peak frequency of the transmission window can be dynamically controlled over a broad frequency range by varying the Fermi energy levels of the graphene layer through controlling the electrostatic gating. The proposed metamaterial structure offers an additional opportunity to design novel applications such as switches or modulators.展开更多
A kind of photonic crystal structure with modulation of the refractive index is investigated both experimentally and theoretically for exploiting electromagnetically induced transparency（EIT）.The combination of EIT ...A kind of photonic crystal structure with modulation of the refractive index is investigated both experimentally and theoretically for exploiting electromagnetically induced transparency（EIT）.The combination of EIT with periodically modulated refractive index medium gives rise to high efficiency reflection as well as forbidden transmission in a threelevel atomic system coupled by standing wave.We show an accurate theoretical simulation via transfer-matrix theory,automatically accounting for multilayer reflections,thus fully demonstrate the existence of photonic crystal structure in atomic vapor.展开更多
The propagation of a probe field through a four-level Y-type atomic system is described in the presence of two additional coherent radiation fields,namely,the control field and the coupling field.An expression for the...The propagation of a probe field through a four-level Y-type atomic system is described in the presence of two additional coherent radiation fields,namely,the control field and the coupling field.An expression for the probe response is derived analytically from the optical Bloch equations under steady state condition to study the absorptive properties of the system under probe field propagation through an ensemble of stationary atoms as well as in a Doppler broadened atomic vapor medium.The most striking result is the conversion of electromagnetically induced transparency(EIT)into electromagnetically induced absorption(EIA)as we start switching from weak probe regime to strong probe regime.The dependence of this conversion on residual Doppler averaging due to wavelength mismatch is also shown by choosing the coupling transition as a Rydberg transition.展开更多
A reflection-type electromagnetically induced transparency（EIT） metamaterial is proposed, which is composed of a dielectric spacer sandwiched with metallic patterns and metallic plane. Experimental results of THz ti...A reflection-type electromagnetically induced transparency（EIT） metamaterial is proposed, which is composed of a dielectric spacer sandwiched with metallic patterns and metallic plane. Experimental results of THz time domain spectrum（THz-TDS） exhibit a typical reflection of EIT at 0.865 THz, which are in excellent agreement with the full-wave simulations. A multi-reflection theory is adopted to analyze the physical mechanism of the reflection-type EIT, showing that the reflection-type EIT is a superposition of multiple reflection of the transmission EIT. Such a reflection-type EIT provides many applications based on the EIT effect, such as slow light devices and nonlinear elements.展开更多
Electromagnetically induced transparency （EIT） is obtained in a symmetric U-shaped metamaterial, which is at- tributed to the simultaneously excited dual modes in a single resonator under lateral incidence. A large ...Electromagnetically induced transparency （EIT） is obtained in a symmetric U-shaped metamaterial, which is at- tributed to the simultaneously excited dual modes in a single resonator under lateral incidence. A large group index accom- panied with a sharp EIT-like transparency window offers potential applications for slowing down light and sensing.展开更多
We study a three-mode double-cavity optomechanical system in which an oscillating membrane of perfect reflection is inserted between two fixed mirrors of partial transmission. We find that electromagnetically induced ...We study a three-mode double-cavity optomechanical system in which an oscillating membrane of perfect reflection is inserted between two fixed mirrors of partial transmission. We find that electromagnetically induced transparency （EIT） can be realized and controlled in this optomechanical system by adjusting the relative intensity and the relative phase between left-hand and right-hand input （probe and coupling） fields. In particular, one perfect EIT window is seen to occur when the two probe fields are exactly out of phase and the EIT window＇s width is very sensitive to the relative intensity of two coupling fields. Our numerical findings may be extended to achieve optomechanical storage and switching schemes applicable in quantum information processing.展开更多
Optical nanofiber(ONF)is a special tool to achieve the interaction between light and matter with ultralow power.In this paper,we demonstrate V-type electromagnetically induced transparency(EIT)in cold atoms trapped by...Optical nanofiber(ONF)is a special tool to achieve the interaction between light and matter with ultralow power.In this paper,we demonstrate V-type electromagnetically induced transparency(EIT)in cold atoms trapped by an ONFbased two-color optical lattice.At an optical depth of 7.35,90%transmission can be achieved by only 7.7 pW coupling power.The EIT peak and linewidth are investigated as a function of the coupling optical power.By modulating the pWlevel control beam of the ONF-EIT system in sequence,we further achieve efficient and high contrast control of the probe transmission,as well as its potential application in the field of quantum communication and quantum information science by using one-dimensional atomic chains.展开更多
We have experimentally offset-locked the frequencies of two lasers using electromagnetically induced transparency（EIT） spectroscopy of ^（85）Rb vapor with a buffer gas in a magnetic field at room temperature. The m...We have experimentally offset-locked the frequencies of two lasers using electromagnetically induced transparency（EIT） spectroscopy of ^（85）Rb vapor with a buffer gas in a magnetic field at room temperature. The magnetic field is generated by a permanent magnet mounted on a translation stage and its field magnitude can be varied by adjusting the distance between the magnet and Rb cell, which maps the laser locking frequency to the space position of the magnet. This frequency-space mapping technique provides an unambiguous daily laser frequency detuning operation with high accuracy.A repeatability of less than 0.5 MHz is achieved with the locking frequency detuned up to 184 MHz when the magnetic field varies from 0 up to 80 G.展开更多
We have studied the phenomenon of electromagnetically induced transparency（EIT） of ^87Rb vapor with a buffer gas in a magnetic field at room temperature. It is found that the spectral lines caused by the velocity se...We have studied the phenomenon of electromagnetically induced transparency（EIT） of ^87Rb vapor with a buffer gas in a magnetic field at room temperature. It is found that the spectral lines caused by the velocity selective optical pump effects get much weaker and wider when the sample cell is mixed with a 5-Torr N_2 gas while the EIT signal is kept almost unchanged. A weighted least-square fit is also developed to remove the Doppler broadening completely. This spectral method provides a way to measure the Zeeman splitting with high resolution, for example, the Λ-type EIT resonance splits into four peaks on the D_2 line of ^87Rb in the thermal 2-cm vapor cell with a magnetic field along the electric field of the linearly polarized coupling laser. The high-resolution spectrum can be used to lock the laser to a given frequency by tuning the magnetic field.展开更多
We present a laser frequency locking to Rydberg transition with electromagnetically induced transparency（EIT）spectra in a room-temperature cesium vapor cell. Cesium levels 6S_（1/2）, 6P_（3/2）, and the n D_（5/2）...We present a laser frequency locking to Rydberg transition with electromagnetically induced transparency（EIT）spectra in a room-temperature cesium vapor cell. Cesium levels 6S_（1/2）, 6P_（3/2）, and the n D_（5/2） state, compose a cascade three-level system, where a coupling laser drives Rydberg transition, and probe laser detects the EIT signal. The error signal, obtained by demodulating the EIT signal, is used to lock the coupling laser frequency to Rydberg transition. The laser frequency fluctuation, ~0.7 MHz, is obtained after locking on, with the minimum Allan variance to be 8.9 × 10^（-11）.This kind of locking method can be used to stabilize the laser frequency to the excited transition.展开更多
We study the ultraslow optical solitons in a resonant three-level atomic system via electromagnetically induced transparency under a density-matrix （DM） approach. The results of linear and nonlinear optical properti...We study the ultraslow optical solitons in a resonant three-level atomic system via electromagnetically induced transparency under a density-matrix （DM） approach. The results of linear and nonlinear optical properties are compared with those obtained by using an amplitude variable （AV） approach. It is found that the results for both approaches are the same in the linear regime if the corresponding relations between the population-coherence decay rates in the DM approach and the energy-level decay rates in the AV approach are appropriately imposed. However, in the nonlinear regime there is a small difference for the self-phase modulation coefficient of the nonlinear SchrSdinger equation that governs the time evolution of probe pulse envelope. All analytical predicts are checked by numerical simulations.展开更多
Electromagnetically induced transparency （EIT） is investigated in a system of cold, interacting cesium Rydberg atoms. The utilized cesium levels 6S1/2, 6P3/2 and nD5/2 constitute a cascade three-level system, in whi...Electromagnetically induced transparency （EIT） is investigated in a system of cold, interacting cesium Rydberg atoms. The utilized cesium levels 6S1/2, 6P3/2 and nD5/2 constitute a cascade three-level system, in which a coupling laser drives the Rydberg transition, and a probe laser detects the EIT signal on the 6S1/2 to 6/23/2 transition. Rydberg EIT spectra are found to depend on the strong interaction between the Rydberg atoms. Diminished EIT transparency is obtained when the Rabi frequency of the probe laser is increased, whereas the corresponding linewidth remains unchanged. To model the system with a three-level Linclblad equation, we introduce a Rydberg-level dephasing rate γ3 = κ×（P33/Ωp）^2, with a value κ that depends on the ground-state atom density and the Rydberg level, The simulation results are largely consistent with the measurements. The experiments, in which the principal quantum number is varied between 30 and 43, demonstrate that the EIT reduction observed at large Ωp is due to the strong interactions between the Rydberg atoms.展开更多
The linewidth of electromagnetically induced transparency（EIT） in a coated Rb vapor cell was studied under a magnetic field gradient.The nonlinear broadening of the EIT linewidth with the magnetic field gradient was...The linewidth of electromagnetically induced transparency（EIT） in a coated Rb vapor cell was studied under a magnetic field gradient.The nonlinear broadening of the EIT linewidth with the magnetic field gradient was observed.It was found that the motional averaging of the field gradient was more pronounced at higher laser intensities and larger beam sizes.In the same regime,there was a small linewidth decrease with the increasing magnetic field gradient.We have established a Monte-Carlo model,which gave results in good qualitative agreement with our experiment.Physics pictures for the above phenomena were also suggested.These results provide an understanding of the EIT linewidth behavior under motional averaging,and should be useful for applications in quantum optics and metrology based on coated vapor cells.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10974126 and 60821004)the National Basic Research Program of China (Grant No. 2010CB923102)
文摘The quantum noise of squeezed probe light passing through an atomic system with different electromagnetically induced transparency and AutlewTownes splitting effects is investigated theoretically. It is found that the optimal squeezing preservation of the outgoing probe beam occurs in the strong-coupling-field regime rather than in the weak- coupling-field regime. In the weak-coupling-field regime, which was recently recognized as the electromagnetically induced transparency regime （Abi-Salloum T Y 2010 Phys. Rev. A 81 053836）, the output amplitude noise is affected mainly by the atomic noise originating from the random decay process of atoms. While in the strong-coupling-field regime, defined as the Autler-Townes splitting regime, the output amplitude noise is affected mainly by the phase-to- amplitude conversion noise. This is useful in improving the quality of the experiment for efficient quantum memory, and hence has an application in quantum information processing.
文摘We would like to point out the misprinted Fig.3 in our published paper[Chin.Phys.B 32,114205(2023)].Since only orders of subfigures need to be corrected and the main results of the published paper are correct,we present the correct figure in this corrigendum.
基金Project supported by the National Natural Science Foundation of China(Grant No.11774098)the Guangdong Natural Science Foundation(Grant Nos.2022A1515011950 and 2023A1515010781)the Science and Technology Program of Guangzhou(Grant No.202002030500)。
文摘We analytically and numerically investigate a signal light storing mechanism based on the controllable electromagnetically induced transparency(EIT)effect.We demonstrate that the isolation between the waveguide and the cavities cannot be achieved instantly as soon as the two cavities are tuned into resonance,no matter the index tuning rate is ultrafast or slow.We also investigate the temporal evolution features of the intracavity energy when the pulse during time is prolonged.We find many periodical oscillations of the trapped energy in both cavities,and they are entirely complementary.Our analysis shows that the adiabatic wavelength conversion in both cavities and a phase difference π between them play critical roles in this phenomenon.
基金support from the National Natural Science Foundation of China (Grant Nos. 62075004 and 11804018)the Beijing Natural Science Foundation (Grant No. 4212051)。
文摘In recent years, most studies have focused on the perfect absorption and high-efficiency quantum memory of the onesided system, ignoring the characteristics of its optical switching contrast. Thus, the performance of all-optical switching and optical transistors is limited. Herein, we propose a localized surface plasmon(LSP) mode-assisted cavity QED system which consists of a Λ-shaped three-level quantum emitter(QE), a metal nanoparticle and a one-sided optical cavity with a fully reflected mirror. In this system, the QE coherently couples to the cavity and LSP mode respectively, which is manipulated by the control field. As a result, considerably high and stable switch contrast of 90% can be achievable due to the strong confined field of the LSP mode and perfect absorption of the optical medium. In addition, we obtain a power dependent effect between the control field and the transmitted frequency as a result of the converted dark state. We employ the Heisenberg–Langevin equation and numerical master equation formalisms to explain high switching, controllable output light and the dark state. Our system introduces an effective method to improve the performance of optical switches based on the one-sided system in quantum information storage and quantum communication.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12034012, 12074231, 12274272, and 61827824)Science and technology innovation plan of colleges and universities in Shanxi Province (Grant No. 2021L313)+2 种基金Science and Technology Project of State Grid (Grant No. 5700-202127198A-0-0-00)Fundamental Research Program of Shanxi Province (Grant No. 202203021222204)Taiyuan University of Science and Technology Scientific Research Initial Funding (Grant Nos. 20222008 and 20222132)。
文摘We demonstrate a simple method to measure electric field intensity by using doublet electromagnetically induced transparency(EIT) spectra of cold Rb Rydberg atoms, where the frequency of the coupling laser does not need to be locked. Based on the Stark splitting of the Rb Rydberg state, 10D_(3/2), under electric fields and the corresponding calculated polarizabilities, the real electric field intensity is calculated using the difference in radio-frequency diffraction between two acousto-optic modulators, which acts as a frequency criterion that allows us to measure the electrical field without locking the coupling laser. The value measured by this simple method shows a good agreement with our previous work [Opt.Express 29 1558(2021)] where the frequency of the coupling laser needs to be locked with an additional EIT spectrum based on atom vapor and a proportional–integral–differential feedback circuit. Our presented method can also be extended to the measurement of electric field based on hot Rydberg atom vapor, which has application in industry.
基金the National Key R&D Program of China(Grant No.2017YFA0304401)the Technical Innovation Program of Hubei Province(Grant No.2018AAA045)the National Natural Science Foundation of China(Grant No.11904387)。
文摘We report on electromagnetically induced transparency cooling of ^(40)Ca^(+)to sympathetically cool the threedimensional secular modes of motion in a ^(40)Ca^(+)–^(27)Al^(+)two-ion pair near the ground state.We observe simultaneous ground state cooling across all radial modes and axial modes of a ^(40)Ca^(+)–^(27)Al^(+)ion pair,occupying a broader cooling range in frequency space over 3 MHz.The cooling time is observed to be less than 1 ms.The mean phonon number and heating rates of all motional modes are measured.This study is not only an important step for reducing the secular motion time-dilation shift uncertainty and uptime ratio of ^(27)Al^(+)optical clock,but also essential for high-fidelity quantum simulations and quantum information processors using trapped ions.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0304203)the National Natural Science Foundation of China(Grant Nos.61675120,11434007,and 61875110)+2 种基金Project of the National Natural Science Foundation of China for Excellent Research Team(Grant No.61121064)the Shanxi “1331 Project” Key Subjects Construction,PCSIRT,China(Grant No.IRT_17R70)the 111 Project,China(Grant No.D18001)
文摘Optical nanofiber(ONF) is a special tool for effectively controlling coupling of light and atoms. In this paper, we study the ladder-type electromagnetically induced transparent(EIT) under ultralow power level in a warm cesium vapor by observing the transmission of ONF that couples the 6 S → 6 P Cs atoms in the presence of a 6 P → 8 S control beam through the same fiber. The linewidth and transmission of the EIT signal are investigated at different intensities of the control laser. In addition, we theoretically study the nonlinear interaction at the ONF interface using the multi-level density matrix equations, and obtain good agreements between theory and experiments. The results may have great significance for further study of optical nonlinear effect at low power level.
基金supported by the National Natural Science Foundation of China(Grant No.61307052)the Youth Funding for Science&Technology Innovation in Nanjing University of Aeronautics and Astronautics,China(Grant No.NS2014039)+3 种基金the Chinese Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20123218110017)the Innovation Program for Graduate Education of Jiangsu Province,China(Grant Nos.KYLX 0272,CXZZ13 0166,and CXLX13 155)the Open Research Program in National State Key Laboratory of Millimeter Waves of China(Grant No.K201609)the Fundamental Research Funds for the Central Universities of China(Grant No.kfjj20150407)
文摘A graphene-based metamaterial with tunable electromagnetically induced transparency （EIT）-like transmission is nu- merically studied in this paper. The proposed structure consists of a graphene layer composed of coupled cut-wire pairs printed on a substrate. The simulation confirms that an EIT-like transparency window can be observed due to indirect cou- pling in a terahertz frequency range. More importantly, the peak frequency of the transmission window can be dynamically controlled over a broad frequency range by varying the Fermi energy levels of the graphene layer through controlling the electrostatic gating. The proposed metamaterial structure offers an additional opportunity to design novel applications such as switches or modulators.
基金Project supported by the National Natural Science Foundation of China(Grant No.11574188)the Project for Excellent Research Team of the National Natural Science Foundation of China(Grant No.61121064)
文摘A kind of photonic crystal structure with modulation of the refractive index is investigated both experimentally and theoretically for exploiting electromagnetically induced transparency（EIT）.The combination of EIT with periodically modulated refractive index medium gives rise to high efficiency reflection as well as forbidden transmission in a threelevel atomic system coupled by standing wave.We show an accurate theoretical simulation via transfer-matrix theory,automatically accounting for multilayer reflections,thus fully demonstrate the existence of photonic crystal structure in atomic vapor.
基金UGC (ERO) for granting a minor research project (F. No. PSW: 050(2015–16), date-16/11/2016)UGC (New Delhi) for providing research fellowship (JRF-NET, vide sanction No. F.17-124/2008(SAI) dated 22/08/2014)+1 种基金SERB for granting a project under Teaching Associateship for Research Excellence (TARE) scheme (sanction no. TAR/2018/000710)the University Grants Commission (New Delhi) for sanctioning a major research project (F. No-43–527/2014(SR) dated 28/09/2015).
文摘The propagation of a probe field through a four-level Y-type atomic system is described in the presence of two additional coherent radiation fields,namely,the control field and the coupling field.An expression for the probe response is derived analytically from the optical Bloch equations under steady state condition to study the absorptive properties of the system under probe field propagation through an ensemble of stationary atoms as well as in a Doppler broadened atomic vapor medium.The most striking result is the conversion of electromagnetically induced transparency(EIT)into electromagnetically induced absorption(EIA)as we start switching from weak probe regime to strong probe regime.The dependence of this conversion on residual Doppler averaging due to wavelength mismatch is also shown by choosing the coupling transition as a Rydberg transition.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61205096 and 61271066)
文摘A reflection-type electromagnetically induced transparency（EIT） metamaterial is proposed, which is composed of a dielectric spacer sandwiched with metallic patterns and metallic plane. Experimental results of THz time domain spectrum（THz-TDS） exhibit a typical reflection of EIT at 0.865 THz, which are in excellent agreement with the full-wave simulations. A multi-reflection theory is adopted to analyze the physical mechanism of the reflection-type EIT, showing that the reflection-type EIT is a superposition of multiple reflection of the transmission EIT. Such a reflection-type EIT provides many applications based on the EIT effect, such as slow light devices and nonlinear elements.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11174051,11004026,11074034,and 61271057)the National Basic Research Program of China (Grant No.2010CB923401)the Youth Study Plan from Southeast University
文摘Electromagnetically induced transparency （EIT） is obtained in a symmetric U-shaped metamaterial, which is at- tributed to the simultaneously excited dual modes in a single resonator under lateral incidence. A large group index accom- panied with a sharp EIT-like transparency window offers potential applications for slowing down light and sensing.
基金supported by the National Natural Science Foundation of China(Grant No.61378094)
文摘We study a three-mode double-cavity optomechanical system in which an oscillating membrane of perfect reflection is inserted between two fixed mirrors of partial transmission. We find that electromagnetically induced transparency （EIT） can be realized and controlled in this optomechanical system by adjusting the relative intensity and the relative phase between left-hand and right-hand input （probe and coupling） fields. In particular, one perfect EIT window is seen to occur when the two probe fields are exactly out of phase and the EIT window＇s width is very sensitive to the relative intensity of two coupling fields. Our numerical findings may be extended to achieve optomechanical storage and switching schemes applicable in quantum information processing.
基金supported by State Grid science and Technology Project(Grant No.5700-202127198A-0-0-00)。
文摘Optical nanofiber(ONF)is a special tool to achieve the interaction between light and matter with ultralow power.In this paper,we demonstrate V-type electromagnetically induced transparency(EIT)in cold atoms trapped by an ONFbased two-color optical lattice.At an optical depth of 7.35,90%transmission can be achieved by only 7.7 pW coupling power.The EIT peak and linewidth are investigated as a function of the coupling optical power.By modulating the pWlevel control beam of the ONF-EIT system in sequence,we further achieve efficient and high contrast control of the probe transmission,as well as its potential application in the field of quantum communication and quantum information science by using one-dimensional atomic chains.
基金Project supported by the National Key Basic Research Program of China(Grant No.2013CB922003)the National Natural Science Foundation of China(Grant Nos.91421305,91121005,and 11174329)
文摘We have experimentally offset-locked the frequencies of two lasers using electromagnetically induced transparency（EIT） spectroscopy of ^（85）Rb vapor with a buffer gas in a magnetic field at room temperature. The magnetic field is generated by a permanent magnet mounted on a translation stage and its field magnitude can be varied by adjusting the distance between the magnet and Rb cell, which maps the laser locking frequency to the space position of the magnet. This frequency-space mapping technique provides an unambiguous daily laser frequency detuning operation with high accuracy.A repeatability of less than 0.5 MHz is achieved with the locking frequency detuned up to 184 MHz when the magnetic field varies from 0 up to 80 G.
基金Project supported by the National Key Basic Research Program of China(Grant No.2013CB922003)the National Natural Science Foundation of China(Grant Nos.91421305,91121005,11674359,and 91436106)
文摘We have studied the phenomenon of electromagnetically induced transparency（EIT） of ^87Rb vapor with a buffer gas in a magnetic field at room temperature. It is found that the spectral lines caused by the velocity selective optical pump effects get much weaker and wider when the sample cell is mixed with a 5-Torr N_2 gas while the EIT signal is kept almost unchanged. A weighted least-square fit is also developed to remove the Doppler broadening completely. This spectral method provides a way to measure the Zeeman splitting with high resolution, for example, the Λ-type EIT resonance splits into four peaks on the D_2 line of ^87Rb in the thermal 2-cm vapor cell with a magnetic field along the electric field of the linearly polarized coupling laser. The high-resolution spectrum can be used to lock the laser to a given frequency by tuning the magnetic field.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB921603)the National Natural Science Foundation of China(Grants Nos.11274209,61475090,61378039,and 61378013)the Research Project Supported by Shanxi Scholarship Council of China(Grant No.2014-009)
文摘We present a laser frequency locking to Rydberg transition with electromagnetically induced transparency（EIT）spectra in a room-temperature cesium vapor cell. Cesium levels 6S_（1/2）, 6P_（3/2）, and the n D_（5/2） state, compose a cascade three-level system, where a coupling laser drives Rydberg transition, and probe laser detects the EIT signal. The error signal, obtained by demodulating the EIT signal, is used to lock the coupling laser frequency to Rydberg transition. The laser frequency fluctuation, ~0.7 MHz, is obtained after locking on, with the minimum Allan variance to be 8.9 × 10^（-11）.This kind of locking method can be used to stabilize the laser frequency to the excited transition.
基金Project supported by National Natural Science Foundation of China (Grant Nos. 10674060,10874043 and 10974181)by the National Basic Research Program of China (Grant Nos. 2005CB724508 and 2006CB921104)
文摘We study the ultraslow optical solitons in a resonant three-level atomic system via electromagnetically induced transparency under a density-matrix （DM） approach. The results of linear and nonlinear optical properties are compared with those obtained by using an amplitude variable （AV） approach. It is found that the results for both approaches are the same in the linear regime if the corresponding relations between the population-coherence decay rates in the DM approach and the energy-level decay rates in the AV approach are appropriately imposed. However, in the nonlinear regime there is a small difference for the self-phase modulation coefficient of the nonlinear SchrSdinger equation that governs the time evolution of probe pulse envelope. All analytical predicts are checked by numerical simulations.
基金Supported by the National Basic Research Program of China under Grant No 2012CB921603Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China under Grant No IRT13076+2 种基金the State Key Program of the National Natural Science of China under Grant No 11434007the National Natural Science of China under Grant Nos 11274209,61475090,60378039 and 61378013Shanxi Scholarship Council of China(2014-009)
文摘Electromagnetically induced transparency （EIT） is investigated in a system of cold, interacting cesium Rydberg atoms. The utilized cesium levels 6S1/2, 6P3/2 and nD5/2 constitute a cascade three-level system, in which a coupling laser drives the Rydberg transition, and a probe laser detects the EIT signal on the 6S1/2 to 6/23/2 transition. Rydberg EIT spectra are found to depend on the strong interaction between the Rydberg atoms. Diminished EIT transparency is obtained when the Rabi frequency of the probe laser is increased, whereas the corresponding linewidth remains unchanged. To model the system with a three-level Linclblad equation, we introduce a Rydberg-level dephasing rate γ3 = κ×（P33/Ωp）^2, with a value κ that depends on the ground-state atom density and the Rydberg level, The simulation results are largely consistent with the measurements. The experiments, in which the principal quantum number is varied between 30 and 43, demonstrate that the EIT reduction observed at large Ωp is due to the strong interactions between the Rydberg atoms.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61078013 and J1103204)the Shanghai Pujiang Program,China (Grant No. 10PJ1401400)+1 种基金the National Basic Research Program of China (Grant Nos. 2011CB921604 and 2012CB921604)the Fudan University,China
文摘The linewidth of electromagnetically induced transparency（EIT） in a coated Rb vapor cell was studied under a magnetic field gradient.The nonlinear broadening of the EIT linewidth with the magnetic field gradient was observed.It was found that the motional averaging of the field gradient was more pronounced at higher laser intensities and larger beam sizes.In the same regime,there was a small linewidth decrease with the increasing magnetic field gradient.We have established a Monte-Carlo model,which gave results in good qualitative agreement with our experiment.Physics pictures for the above phenomena were also suggested.These results provide an understanding of the EIT linewidth behavior under motional averaging,and should be useful for applications in quantum optics and metrology based on coated vapor cells.
