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利用腔内量子电动力学效应改变钕玻璃微球荧光谱特性的研究 总被引:3,自引:1,他引:2
报道腔内量子电动力学效应对钕玻璃微球荧光谱的影响;分析了光谱中量子电动力学结构的相对强度,同时估算了自发辐射速率的量子电动力学增强。实验证实增强辐度超过16倍。 相似文献
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Bose-Einstein Condensates in a One-Dimensional Optical Lattice: from Superfluidity to Number-Squeezed States 下载免费PDF全文
We study the phase coherence property of Bose-Einstein condensates confined in a one-dimensional optical lattice formed by a standing-wave laser field. The lattice depth is determined using a method of Kapitza-Dirac scattering between a condensate and a short pulse lattice potential. Condensates are then adiabatically loaded into the optical lattice. The phase coherence property of the confined condensates is reflected by the interference patterns of the expanded atomic cloud released from the optical lattice. For weak lattice, nearly all of the atoms stay in a superfluid state. However, as the lattice depth is increased, the phase coherence of the whole condensate sample is gradually lost, which confirms that the sub-condensates in each lattice well have evolved into number-squeezed states. 相似文献
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Jin-Qi Wang 《中国物理 B》2022,31(9):90601-090601
Sideband cooling is a key technique for improving the performance of optical atomic clocks by preparing cold atoms and single ions into the ground vibrational state. In this work, we demonstrate detailed experimental research on pulsed Raman sideband cooling in a $^{171}$Yb optical lattice clock. A sequence comprised of interleaved 578 nm cooling pulses resonant on the 1st-order red sideband and 1388 nm repumping pulses is carried out to transfer atoms into the motional ground state. We successfully decrease the axial temperature of atoms in the lattice from 6.5 μK to less than 0.8 μK in the trap depth of 24 μK, corresponding to an average axial motional quantum number $\langle n_z\rangle<0.03$. Rabi oscillation spectroscopy is measured to evaluate the effect of sideband cooling on inhomogeneous excitation. The maximum excitation fraction is increased from 0.8 to 0.86, indicating an enhancement in the quantum coherence of the ensemble. Our work will contribute to improving the instability and uncertainty of Yb lattice clocks. 相似文献
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We report the experimental realization of a magneto-optical trap (MOT) of ^174 Yb atoms operating on the ^1 So -^3 P1 intereombination transition at 555.8nm. The green MOT is loaded by a Zeeman-slowed atomic beam. In order to increase the capture velocity of the MOT, we use the trapping laser beams consisting of five discrete frequency components obtained by modulating the laser light through an electro-optic modulator. The trapped atomic number of the ^174Yb isotope is about 6.2 × 105, and the temperature of the cold atomic cloud is estimated to be about 100μK. The success of the green MOT is an clock. important step towards the goal of an ytterbium optical 相似文献
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Quantum degenerate gases of alkaline-earth-like atoms are unique systems used for quantum simulation, quantum computing and studies of quantum phase transitions. We report an all-optical formation of Bose Einstein eondensates of ytterbium atoms. About 106 atoms of ^174Yb are transferred to a far-off-resonance optical trap (FORT) and then cooled by evaporative cooling. Phase transition occurs at the critical temperature of 520 nK. A pure condensate containing approximately 2 × 10^4 atoms has been obtained in the crossed FORT, with an atomic peak density of -8 × 10^14 cm^-3. The condensate lifetime exceeds 1 s. 相似文献
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A frequency-stabilized 556-nm laser is an essential tool for experimental studies associated with 1 S 0-3 P 1 intercombination transition of ytterbium (Yb) atoms.A 556-nm laser light using a single-pass second harmonic generation (SHG) is obtained in a periodically poled MgO:LiNbO 3 (PPLN) crystal pumped by a fiber laser at 1111.6 nm.A robust frequency stabilization method which facilitates the control of laser frequency with an accuracy better than the natural linewidth (187 kHz) of the intercombination line is developed.The short-term frequency jitter is reduced to less than 100 kHz by locking the laser to a home-made reference cavity.A slow frequency drift is sensed by the 556-nm fluorescence signal of an Yb atomic beam excited by one probe beam and is reduced to less than 50-kHz by a computer-controlled servo system.The laser can be stably locked for more than 5 h.This frequency stabilization method can be extended to other alkaline-earth-like atoms with similar weak intercombination lines. 相似文献
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Low-Energy Collective Excitation of Bose-Einstein Condensates in an Anisotropic Magnetic Trap 下载免费PDF全文
We experimentally investigate the collective excitation of 87Rb Bose-Einstein condensates confined in a cigarshaped magnetic trap (QUIC trap). Using a method of magnetic perturbation, the center-of-mass oscillation of the condensate is excited, so that the radial trapping frequency of the QUIC trap can be precisely determined. A high-order excitation, characterized by a fast shape oscillation, also occurs simultaneously, with a noticeable damping in the oscillation amplitude compared with the oscillation of the center of mass. The measured oscillation frequencies, associated with these two low-energy excitation modes, agree well with theoretical predictions based on the Gross-Pitaevskii equation. 相似文献
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We build a Zeeman slower with consecutive coils and use it to load an Yb magneto-optical trap(MOTs).Cooling efficiency is measured by the fluorescence intensity of the atomic cloud trapped by the MOT.An optimized magnetic field profile can acquire the maximum cooling efficiency,corresponding to a good compromise between the smaller magnetic field mismatch and the high capture velocity.Our studies provide useful information on how the performance of the Zeeman slower can be improved. 相似文献