Li Dai-Jun

Control of Cold Atoms by Slow Waves in a Hollow Fibre

We propose that a slowly-moving standing wave can be used to manipulate the motion of an atomic wave packet in a hollow optical fibre. A cloud of cold atoms can follow the motion of such a slow wave. The evolution of an initial Gaussian atomic wave packet in the moving standing wave is calculated by numerically solving the Schrodinger equation. Our calculation shows that by using a sufficiently strong field and by adjusting the velocity of the standing wave pattern, the motion of the atomic cloud can be controlled in a hollow fibre.

Nonlinear Theory of Light Speed Reduction in a Three-Level Λ System

We present a nonlinear theory of light velocity reduction in a three-level Λ system based on electromagnetically induced transparency. Analysis shows that the probe field propagates with a velocity that is quite strongly dependent on its intensity instead of being merely approximately dependent on the coupling intensity. Moreover, the minimum group velocity of the probe field is analytically given for a given input power.

A Compact 532-nm Source by Frequency Doubling of a Diode Stack End-Pumped Nd:YAG Slab Laser

A near-diffraction-limited green source is generated at 1 kHz repetition rate by frequency doubling of a diode stack end-pumped electro-optically Q-switched Nd:YAG slab laser. We obtain 9.7 mJ green light with pulse width of 12.2 ns at a repetition rates of 1 kHz. The pump to green optical conversion efficiency is 12.9%. The energy pulse stability at 532 nm is about 0.8%.

Diode Stack End-Pumped Nd:GdVO4 Continuous Wave Slab Laser

We report a diode stack end-pumped Nd:GdVO4 slab laser with a near-diffraction-limited beam. The output power of 45.8 W at 1064 nm is obtained under the pumping power of 147 W, with the optical-optical conversion efficiency of 31.2%, and the slope efficiency is 39.6%.

The periodic magnetic cylinder tube for atom guidance: transport efficiency analysis

We have proposed a model of periodic axial magnetized hollow tube for atom guidance (1999 Opt. Commun. 160 72-4). In the present paper, an analytic solution of the magnetic field inside the tube is obtained and the transport efficiency of the cold atoms in the magnetic tube at different tube intensities of magnetization is discussed. The effect of the curvature of magnetic tube on the atom transport efficiency is also considered. We have found that the tube has a cooling effect on the transverse temperature of the transported atoms.

Atomic Interaction Effects on Electromagnetically Induced Transparency and Slow Light in Ultracold Bose Gas

We investigate electromagnetically induced transparency and slow group velocity of light in ultracold Bose gas with a two-photon Raman process. The properties of electromagnetically induced transparency and light speed can be changed by controlling the atomic interaction. Atomic interaction can be used as a knob to control the optical properties of atomic media. This can be realized in experiment by using the Feshbach resonance technique.

Stimulated Raman Adiabatic Population Transfer of Two Bose-Einstein Condensates

Considering all the ground-state atom interactions, we investigate the population transfer of two Bose-Einstein condensate (BEC) states, which are trapped in different potential wells, or two ground states of the BEC in the same trap using the stimulated Raman adiabatic process. With a proper choice of pulsed geometric parameters, the dark state exists. By simply choosing ground-state detunings, the effects of the interatomic interaction can be suppressed and a high population transfer rate can be obtained.

Quantum Motion of Atoms in a Magnetic Waveguide

Based on the magnetic atomic guidance model proposed in our previous paper [Opt. Commun. 160(1999)72], the quantum motion of atoms in a magnetic tube is discussed in detail. The non-adiabatic loss of atoms as result of spin-flip transition and the adiabatic condition for keeping atoms in the guidable state are also analysed. The result shows that the atoms can be guided in the magnetic waveguide with a higher guiding efficiency by choosing suitable parameters of the magnetic tube.