| Light is a better carrier of information, so the optical information transmission and storage is particularly important in the medium. While electromagnetically induced transparency has become a versatile tool for realization of controllable atom-light coupling. It occurs when two resonant light fields excite two ground-state sub-levels to a single upper level. In the case of EIT, the atom is trapped in a coherent dark ground-state and prevents its excitation to the upper level. This allows the probing light beam to pass the medium; otherwise it would have been completely opaquely. The characteristic of strong dispersion and high transmission, can realize light slowed down. At the same time, through adiabatically control of coupling light off-on, we can extract the light signal which stored in the medium. The realization of slow light and optical storage technology based on EIT has great application prospect in the field of quantum computation and quantum communication. In this paper we encompassment the optical storage in atom medium to complete the following work. Firstly, we find the window of EIT can be used for a low pass filter. Secondly, we get the whole and the part of the fractions of Gauss pulses by controlling delay time of slow pulses. Thirdly, we realization of cold gases of atoms with the magneto-optical trap (MOT), which establish foundation for further research of optical information storage in cold atoms.The main results were given as follows:1. A set of experimental system was designed and built based on the technology of EIT, which is using for studying slow light and optical pulse storage and retrieval.2. We have experimentally realized slow light based on Zeeman EIT in rubidium atom. Then find the window of EIT can be used for a low pass filter.3. We analyze the slow light pulse with different t experimental parameters, such as the temperature of atoms, the power of the coupling light, the frequency band of the incident light pulse. Then through adiabatically control the time of coupling light closing and opening, we can retrieve different fractions of the slow light; also we retrieve the nearly total shape in different storage time.4. We have experimentally studied multiple side-band generation for two-frequency components injected into a tapered amplifier (TA) and demonstrated its effects on atomic laser cooling. A heterodyne frequency-beat measurement and a Fabry-Perot interferometer have been applied to analyze the side-band generation with different experimental parameters, such as frequency difference, injection laser power, and TA current. In laser-cooling potassium40 and potassium41 with hyperfine splitting of 1.3 GHz and 254 MHz, respectively, the side-band generation with a small frequency difference has a significant effect on the number of trapped atoms.5. We experimentally demonstrate the enhancement of 6Li trapping efficiency by using the multiple-sideband cooling in a two-dimensional magneto-optical trap (2D MOT). In the 2D MOT, we increase the spectral width of the cooling light to 102 MHz by generating six frequency sidebands in order to couple fast atoms. The capture velocity is dramatically increased by employing the multiple-sideband cooling. The number of trapped atoms in the 3D MOT is 6.0×108, which is higher by a factor of 4 than in the case of single-frequency cooling. We have investigated the dependence of atom number on laser detuning, and our experimental result agrees well with the prediction of a simple two-level model. The efficiency of the multiple-sideband cooling for lithium (in contrast to many other alkali-metal atoms) is also confirmed by the analysis of the loss due to fine-structure changing collisions. |
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