A novel scheme was proposed to form the double-well optical trap by using shift phase gratings. A few pairs of adjustable double-well optical traps for trapping cold atoms or cold molecules were formed on the focal plane when the gratings were illuminated by plane light wave (or TEM00 mode Gaussian light wave) and focused by positive lens. The intensity distribution was calculated, and then the intensity distribution gradients as well as the analytical relations between geometrical parameters of the traps and the parameters of the optical system were derived. At the same time, three different evolution processes from double-well to unit-well were investigated. Also, optical dipole potential and photon scattering rate of the trapped cold atoms were calculated. The results show that the scheme not only is simple and convenient to realize, but also has wide application prospect in many fields, such as atomic physics, atomic optics, molecular optics and quantum optics.
A novel scheme was proposed to form the double-well optical trap by using shift phase gratings. A few pairs of adjustable double-well optical traps for trapping cold atoms or cold molecules were formed on the focal plane when the gratings were illuminated by plane light wave (or TEM00 mode Gaussian light wave) and focused by positive lens. The intensity distribution was calculated, and then the intensity distribution gradients as well as the analytical relations between geometrical parameters of the traps and the parameters of the optical system were derived. At the same time, three different evolution processes from double-well to unit-well were investigated. Also, optical dipole potential and photon scattering rate of the trapped cold atoms were calculated. The results show that the scheme not only is simple and convenient to realize, but also has wide application prospect in many fields, such as atomic physics, atomic optics, molecular optics and quantum optics.
In this paper, we propose a novel scheme to build a controllable four-well optical trap for cold atoms or molecules by using an optical system of a binary π-phase plate and a lens illuminated by a plane light wave. We calculate the intensity distribution of the four-well optical trap, and discuss the evolution process of the optical trap from four wells to two wells or form four wells to a single well, and derive some analytical relations between the characteristic parameters of the four-well trap (including geometric parameters, intensity distribution, intensity gradients and their curvatures) and the parameters of the optical lens system. Our study shows that our four-well trap can be continuously changed into a double-well one or a single-well one by moving the π-phase plate, and the relation between the distance of the trapping centers of the four wells or two wells and the moving distance of the π-phase plate is obtained by data fitting. So our four-well trap scheme has important and wide potential aplications in the fields of ultracold atomic physics, cold molecular physics, atom optics, molecule optics and quantum optics,and even in the fields of quantum calculation and information processing, and so on.
We propose a novel, to our knowledge, scheme to form a controllable double-well optical dipole trap for cold atoms (or molecules) by using an optical system composed of a binary pi-phase plate and a lens illuminated by a plane light wave. We calculate the intensity distribution of the double-well trap and derive the analytical relationships between the characteristic parameters of the double-well trap (including geometric parameters, intensity distributions, and intensity gradients and their curvatures) and the relative aperture beta of the lens system. We also extend our controllable double-well trap to its trap array by using a binary pi-phase grating combined with an array of spherical microlenses. Our study shows that, if the pi-phase plate (or the pi-phase grating) is moved along the x direction, our double-well trap (or array of double-well ones) can continuously evolve to a single-well one (or an array of single-well ones) and vice versa, which can be used to study cold collisions between two atomic (or molecular) samples and atom interference with Bose-Einstein condensation (BEC) in a double-well potential; to prepare quantum entanglement between two macroscopic atomic assembles, even to realize an all-optical double-well atomic (molecular) BEC (including an array of all-optical double-well BECs) by using optical-potential evaporative cooling; to form a novel optical lattice with a larger lattice constant; and so on.
In this paper, we propose a novel scheme to form a controllable doublewell opt i cal trap for cold atoms or molecules by using a system composed of a binary π phase plate and a lens illuminated by a plane light wave. We calculate the int ensi ty distribution of the doublewell trap, and study the evolution process of th e optical trap from two wells to a single well, and derive the analytical relation between the characteristic parameters of the doublewell trap (includi ng g eometric parameters, the intensity distributions, intensity gradients and their curvatures) and the parameters of optical system. We find that our doublewell trap can be continuously changed into a singlewell trap by moving the πphas e pl ate along the x direction, and the relation between the distance of the trap ping centers of the two wells and the moving distance of the πphase plate is obt ain ed by data fitting. In addition, our doublewell scheme is not only simple and c onvenient, but also has some important and wide applications in the fields of at omic physics, atom optics, molecule optics and quantum optics and so on.
We propose a novel scheme to form one- and two-dimensional arrays of double-well optical dipole traps for cold atoms (or molecules) by using an optical system composed of a binary π-phase grating and a lens illuminated by a plane light wave, and study the relationship between the maximum intensity Imax of each optical well (or the maximum trapping potential Umax for ^85Rb atoms) and the relative aperture β (= α/f) of the lens. We also calculate the intensity gradients of each optical well and their curvatures, and estimate the spontaneous photon-scattering rate of trapped atom in each well, including Rayleigh and Raman scattering rates. Our study shows that the proposed 1D and 2D arrays of double-well traps can be used to prepare 1D and 2D novel optical lattices with cold atoms (or molecules), or form an all-optically integrated atom optical chip, or even to realize an array of all-optical double-well atomic (or molecular) Bose-Einstein condensates by optical-potential evaporative cooling, and so on.
We propose a novel scheme to form one- and two-dimensional arrays of double-well optical dipole traps for cold atoms (or molecules) by using an optical system composed of a binary π-phase grating and a lens illuminated by a plane light wave, and study the relationship between the maximum intensity I max of each optical well (or the maximum trapping potential U max for 85 Rb atoms) and the relative aperture β ( = a / f ) of the lens. We also calculate the intensity gradients of each optical well and their curvatures, and estimate the spontaneous photon-scattering rate of trapped atom in each well, including Rayleigh and Raman scattering rates. Our study shows that the proposed 1D and 2D arrays of double-well traps can be used to prepare 1D and 2D novel optical lattices with cold atoms (or molecules), or form an all-optically integrated atom optical chip, or even to realize an array of all-optical double-well atomic (or molecular) Bose–Einstein condensates by optical-potential evaporative cooling, and so on.
In this paper, we propose a novel scheme to produce a longitudinal controllable double-well optical dipole trap for cold atoms (or cold molecules), which is composed of a binary π-phase plate and a lens. The π-phase plate consists of two homocentric rings with equal area and opposite phase (0 and π), and its central region is opaque. When a plane light wave passes through the above optical system, a double-well optical trap will be formed at two sides of the focal point along the optical axis. The outer radius of the binary π-phase plate can be controlled by adjusting the radius of a diaphragm, so that a double-well optical trap will evolve and finally combined into a single-well, or vice versa. We briefly introduce the basic principle and derive several optimal parameters of the trap, and show the dependence of the optical parameters (including intensity distributions) on the geometrical parameters of the system. Our study shows that the proposed controllable optical trap can be used not only to trap cold atoms (or cold molecules) and realize all-optical, double-well or two species Bose-Einstein condensation (BEC), but also to study the trapped-atom (-molecule) interference, or form a 2D array of double-layer optical traps for cold atoms (or molecules), even to prepare a novel 2D optical lattice, and so on.