Novel Schemes To Realize Optical Guiding And Trapping For Cold Atoms Or Molecules

Since Hansch et al proposed an idea on laser cooling atoms in 1975,the theory and experiment of laser cooling,trapping and manipulating of neutral atoms have been developed rapidly,which created a new research field called atom and molecule optics.In this thesis,firstly,basic principles and recent progress on laser guiding and trapping neutral atoms and molecules have been briefly introduced and reviewed. Next,we introduce the development of optical trap array and several methods to realize optical arrays,such as 1) laser-scanning method;2) using diffractive optical element method;3) using vertical cavity surface emitting lasers method;4) using optical imaging fiber bundles method,and so on.We proposed a scheme to realize the optical guiding of neutral cold atoms and molecules by using a single slit diffraction.Firstly,we figured out the axial distribution of light intensity behind the diffraction screen and the transverse intensity distribution at the place of the maximal axial intensity by using Rayleigh-Sommerfeld and Fresnel scalar diffraction theory.Then we propose a novel scheme to improve the red-detuned Gaussian optical guide by using a binary phase plate.We find that with the change of the phaseφ,the central position of the light guiding along the axis,the maximal intensity and guiding width will be changed.Then we discussed the feasibility of guiding I₂ molecule.Finally,we discussed the potential application of this scheme in laser guiding atoms and molecules,all-optical type integrated atomic and molecular optical devices.We proposed a new scheme to realize the optical trap arrays by using the reflective LCD spatial light modulator and study the method to produce the arrays using computer generated hologram.A brief introduction to basic principle of the spatial light modulator is given.Furthermore,several methods to acquire optic wells by computer generated hologram technique are discussed.In the experiment,we use a spatial light modulator based on a reflective liquid crystal on silicone display (LC-R2500) to shape the beam,and get different light patterns such as the points-ring array and cross array,etc.