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1.
双光子拉曼过程是一种有效制备和控制原子内态的方法, 在原子内态操控和基于原子的量子信息处理中具有重要意义. 研制用于特定原子的拉曼激光是实现该过程的重要一步. 报道了利用光纤波导相位调制器及滤波器等实现用于铯原子内态操控的拉曼激光的方法, 并成功用于单个铯原子的内态精密操控. 通过4.6 GHz的微波信号源直接驱动波导相位调制器高效地获得光场的调制边带, 并利用自由光谱区为9.19 GHz的法布里-珀罗腔将载波及二阶边带滤掉, 获得了频率精确、相差9.19 GHz的拉曼激光. 经过基于光纤振幅调制器的功率稳定系统, 最终可以获得总功率为73 μupW、长时间内波动为2.2%的拉曼激光束, 并将此光束用于激发单个铯原子, 实现了|6S1/2, F=4, mF=0和|6S1/2, F=3, mF=0 之间的可控拉比操作. 相似文献
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We present a scheme to generate a squeezed atom laser via stimulated Raman transition of the atoms in Bose-Einstein condensate (BEC) interacting with two light beams, including a weaker squeezed coherent probe light and a stronger classical pump light. The results show that the quantum fluctuation of this atom laser can be periodically squeezed. The squeezing depth of such atom laser is determined by the initial squeezing factor of the probe light, and the squeezing period of that is related to the mean number of atoms in the trap, the strength of interaction between squeezing light and BEC atoms, and the detuning of the light. 相似文献
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We introduce a scheme for creating continuous variable entanglement between an atomic beam and an optical field, by using squeezed light to outcouple atoms from a Bose-Einstein condensate via a Raman transition. We model the full multimode dynamics of the atom laser beam and the squeezed optical field and show that, with appropriate two-photon detuning and two-photon Rabi frequency, the transmitted light is entangled in amplitude and phase with the outcoupled atom laser beam. The degree of entanglement is controllable via changes in the two-photon Rabi frequency of the outcoupling process. 相似文献
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J. Le Gouët P. Cheinet J. Kim D. Holleville A. Clairon A. Landragin F. Pereira Dos Santos 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(3):419-425
In atom interferometers based on two photon transitions,
the delay induced by the difference of the laser beams paths makes
the interferometer sensitive to the fluctuations of the frequency
of the lasers. We first study, in the general case, how the laser
frequency noise affects the performance of the interferometer
measurement. Our calculations are compared with the measurements
performed on our cold atom gravimeter based on stimulated Raman
transitions. We finally extend this study to the case of cold atom
gradiometers. 相似文献
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利用受激Raman跃迁制备的原子激光的相干性 总被引:1,自引:1,他引:0
研究了利用原子玻色-爱因斯坦凝聚体与光相互作用产生受激Raman跃迁制备的原子激光二阶相干性质。结果表明,这种原子激光是反聚束的,在一定条件下,是二阶相干的。 相似文献
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研究了利用原子玻色-爱因斯坦凝聚体与制备的原子激光的二阶相干性质. 结果表明,这种原子激光是反聚束的,在一定条件下,是二阶相干的. 相似文献
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M. K. Olsen S. A. Haine A. S. Bradley J. J. Hope 《The European physical journal. Special topics》2008,160(1):331-342
The development of the Raman atom laser promises to make available new techniques for accessing and manipulating the quantum
statistical properties of Bose-Einstein
condensates. In this work we show how, combined with the already existing methods for the manipulation
of quantum states of light which are central to quantum optics, the Raman input-output coupling mechanisms potentially enable
the production of quadrature squeezed and sub-Poissonian atomic beams, and entanglement between atomic and optical fields.
We also propose a method of measuring the quantum statistics of the atomic beam by transferring them to an optical field.
Finally, by combning these techniques, we propose a method of teleporting the atom laser beam from one trapped condensate
to another. 相似文献
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原子激光器与非线性原子光学:现代原子物理学的新进展 总被引:2,自引:0,他引:2
介绍了当前原子物理实验研究的两项最新突破:准连续全方位可调谐原子激射器(又称原子激射器)以及世界第一个非线性原子光学实验。前者在实现高亮度、高相干性原子激射器的研究方面迈出了极其重要的一步,后者则首次证明了物质波的多波混频效应,从而开辟了一个崭新的研究领域。 相似文献
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Wilpers G Binnewies T Degenhardt C Sterr U Helmcke J Riehle F 《Physical review letters》2002,89(23):230801
We demonstrate how to realize an optical clock with neutral atoms that is competitive to the currently best single ion optical clocks in accuracy and superior in stability. Using ultracold atoms in a Ca optical frequency standard, we show how to reduce the relative uncertainty to below 10(-15). We observed atom interferences for stabilization of the laser to the clock transition with a visibility of 0.36, which is 70% of the ultimate limit achievable with atoms at rest. A novel scheme was applied to detect these atom interferences with the prospect to reach the quantum projection noise limit at an exceptional low instability of 4 x 10(-17) in 1 s. 相似文献
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The coherence of a squeezed sodium atom laser generated from a Raman output coupler, in which the sodium atoms in Bose-Einstein condensate (BEC) interact with two light beams consisting of a weaker squeezed coherent probe light and a stronger classical coupling light, is investigated. The results show that in the case of a large mean number of BEC atoms and a weaker probe light field, the atom laser is antibunching, and this atom laser is second-order coherent if the number of BEC atoms in traps is large enough. 相似文献
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S. Merlet L. Volodimer M. Lours F. Pereira Dos Santos 《Applied physics. B, Lasers and optics》2014,117(2):749-754
We present here a simple laser system for a laser-cooled atom interferometer, where all functions (laser cooling, interferometry and detection) are realized using only two extended cavity laser diodes, amplified by a common tapered amplifier. One laser is locked by frequency modulation transfer spectroscopy, the other being phase locked with an offset frequency determined by an field-programmable gate array-controlled direct digital synthesizer, which allows for efficient and versatile tuning of the laser frequency. Raman lasers are obtained with a double pass acoustooptic modulator. We demonstrate a gravimeter using this laser system, with performances close to the state of the art. 相似文献
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Brightness enhancement in an external cavity diamond Raman laser designed for high power conversion of a neodymium (1064 nm) laser to the eye‐safe spectral region is reported. Using a multimode input beam pulsed at 36 kHz pulse repetition frequency, 16.2 W with 40% overall conversion efficiency was obtained at the second Stokes wavelength of 1485 nm. The output beam had a quality factor of which is a factor of 2.7 times lower than that of the input beam, resulting in a higher overall brightness. The output power, brightness, and brightness enhancement obtained represent significant advances in performance for Raman lasers as well as other competing kHz‐pulsed eye‐safe technologies. 相似文献
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Kwan Kim Yoon Mi Lee Hyang Bong Lee Yeonju Park Tae Yeol Bae Young Mee Jung Cheol Ho Choi Kuan Soo Shin 《Journal of Raman spectroscopy : JRS》2010,41(2):187-192
We have investigated the photochemical characteristics of silver 4‐nitrobenzenethiolate (Ag‐4NBT) by means of Raman spectroscopy. When Ag‐4NBT is irradiated with an argon ion laser at 514.5 nm, its Raman spectrum changes over time, resulting in the production of 4NBT‐capped silver nanoparticles. The surface‐enhanced Raman scattering (SERS) spectrum of 4NBT adsorbed on those Ag nanoparticles is subsequently converted to that of 4‐aminobenzenethiol (4ABT). These surface‐induced photoreduction characteristics were investigated by monitoring the growth of Raman peaks of 4ABT as a function of the laser exposure time. Water vapor or ambient conditions were more effective than vacuum conditions for the photoreduction of 4NBT to 4ABT. Nonetheless, the occurrence of photolysis even under vacuum conditions suggests that the benzene ring hydrogen atoms might be the H‐atom source of the nitro‐to‐amine group conversion although in ambient conditions water or solvent molecules trapped inside the Ag‐4NBT should be the primary H‐atom source and facilitate the transfer of electrons, as well as the diffusion of Ag atoms to form highly SERS‐active nanoaggregates. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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We investigate the generation and the evolution of continuous-variable (CV) entanglement from a laser-driven four-state atom inside a doubly resonant cavity under Raman excitation. Two transitions in the four-state atom independently interact with the two cavity modes, while two other transitions are driven by coupling laser fields. By including the atomic relaxation as well as cavity losses, we show that the CV entanglement with large mean number of
photons can be generated in our scheme. We also show that the intensity of the coupling laser fields can influence effectively the entanglement period of the cavity field. Different from the conventional resonant excitation scheme where zero one-photon detuning are required, it is found that the intensity and period of entanglement between the two cavity modes as well as the total mean photon number of the cavity field can be adjusted by properly
modulating the frequency detuning. 相似文献
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We observed a polarization change induced by laser radiation in the Raman-type three-level atom In in the presence of Ar. The observed two components in the polarization change spectrum of the probe beam correspond to the resonant Raman scattering and the luminescence processes in the spontaneous emission. The dependence of their intensities on the collision with Ar atoms agrees with the theory. 相似文献
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Conclusions The foregoing analysis does not exhaust the analytic methods of laser spectroscopy (see, e.g., [6–8, 142, 143]). The methods of traditional [8–10, 144, 145] resonance [8, 146], and active (or CARS) [8, 11, 147] Raman scattering spectroscopy are continuously being expanded. Newer, purely laser methods — optogalvanic spectroscopy [25, 148], optothermal spectroscopy [7, 149], the method of selective photoionization [6, 150], etc. — are also being developed.Further development of laser spectra analysis will primarily require going beyond narrow laboratory, purely research setups, and the development of commercial laser analytic devices. In this connection, in selecting a method as the basis for the device being constructed it is necessary to know not only the technical characteristics, such as sensitivity, selectivity, speed of operation, etc., but also the metrological characteristics, such as the random and systematic measurement errors; in addition, the measurement accuracy is a decisive factor. At the same time there are few works devoted to the questions of accuracy of the measurements performed with laser spectrometers; in the literature available to us there are no reviews and comparisons of analytic methods of laser spectroscopy from this viewpoint.Amongst the foregoing methods the direct absorption method has the highest accuracy. With a definite arrangement of the measurement process this method enables absolute measurements of the concentration of the analyte component, i.e., it does not require precalibration of the apparatus based on gas mixtures (for the gas analyzer). The minimum achievable error of such measurements is limited by the error of the premeasured absorption coefficient for radiation of the molecule being detected at the wavelength of the laser radiation and at the present time can equal 1–3%. Other methods studied are characterized by higher sensitivity, and they are also more accurate, difficult to calibrate, and less versatile. A comparative analysis of the methods and their errors will be performed in the future.Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 48, No. 1, pp. 7–26, January, 1988.We thank A. P. Voitovich for useful remarks and a discussion of this work. 相似文献