The quantized center of mass(c.m.)motion of a single two-level atom or ion confined in a one-dimensional harmonic potential and interacting with a single-mode classical traveling laser field,is investigated.We show th...The quantized center of mass(c.m.)motion of a single two-level atom or ion confined in a one-dimensional harmonic potential and interacting with a single-mode classical traveling laser field,is investigated.We show that both quadrature and amplitude squared squeezed vibrational states can be generated in this simple trap model when c.m.motion is initially in a certain coherent trap state.展开更多
A novel recipe is proposed to generate nonclassical vibrational states of the center-of mass motions of ions in a quantized trap,based on the quantum conversion between the quantum cavity fields and the quantized trap...A novel recipe is proposed to generate nonclassical vibrational states of the center-of mass motions of ions in a quantized trap,based on the quantum conversion between the quantum cavity fields and the quantized trap.It is shown that,when an ion trap system interacts with the eigen mode of a single-mode Fabry-Pérot cavity where the trap was set in,and a particularly selected external laser pulse through Raman transitions,the interchange of the quantum features between the quantum light states and the quantized trap states occurs.This kind of quantum conversion can be used to prepare some nonclassical trap states in an ion trap as well as to measure the properties of initial nonclassical vibrational states.展开更多
A scheme for the generation of a nonclassical Bose-Einstein condensate is proposed in a J_(g)=1→J_(e)=0 system where ultracold atoms are populated in one ground-state sublevel|g_〉and form a Bose-Einstein condensate....A scheme for the generation of a nonclassical Bose-Einstein condensate is proposed in a J_(g)=1→J_(e)=0 system where ultracold atoms are populated in one ground-state sublevel|g_〉and form a Bose-Einstein condensate.By coupling the condensate to copropagating classical(σ^(-))and quantum(σ^(+))non-resonant travelling-wave laser fields,effective two-photon excitations between two ground-state sublevels|g_〉and|g+〉create a new condensate in|g+〉.For an appropriate selection of the interaction time and atom-field coupling strengths,the quantum features of the quantized laser field,which may be prepared in a certain nonclassical state,can be exchanged with those of the quantum density field of the generated condensate.展开更多
A single-photon detector is an extremely sensitive device capable of registering photons,offering essential technical support for optics quantum information applications.We review herein our recent experimental progre...A single-photon detector is an extremely sensitive device capable of registering photons,offering essential technical support for optics quantum information applications.We review herein our recent experimental progress in the development and application of single-photon detection techniques.Techniques based on advanced self-differencing,low-pass filtering,frequency up-conversion and photon-number-resolving are introduced for attaining high-speed,high-efficiency,low-noise single-photon detection at infrared wavelengths.The advantages of high-speed single-photon detection are discussed in some applications,such as the laser ranging and quantum key distribution.The photon-number-resolving detection is shown to support efficient quantum random number generation.展开更多
The molecular wake-assisted interaction between two collinear femotosecond laser pulses is investigated in air,which leads to the generation of a controllable 1.8 mJ super-continuum pulse with an elongated self-guided...The molecular wake-assisted interaction between two collinear femotosecond laser pulses is investigated in air,which leads to the generation of a controllable 1.8 mJ super-continuum pulse with an elongated self-guided channel due to the cross-phase modulation of the impulsively aligned diatomic molecules in air.For two parallel launched femtosecond laser pulses with a certain spatial separation,controllable attraction and repulsion of the pulses are observed due to the counter-balance among molecular wakes,Kerr and plasma effects,where the molecular wakes show a longer interaction distance than the others to control the propagation of the intense ultrashort laser pulses.展开更多
文摘The quantized center of mass(c.m.)motion of a single two-level atom or ion confined in a one-dimensional harmonic potential and interacting with a single-mode classical traveling laser field,is investigated.We show that both quadrature and amplitude squared squeezed vibrational states can be generated in this simple trap model when c.m.motion is initially in a certain coherent trap state.
文摘A novel recipe is proposed to generate nonclassical vibrational states of the center-of mass motions of ions in a quantized trap,based on the quantum conversion between the quantum cavity fields and the quantized trap.It is shown that,when an ion trap system interacts with the eigen mode of a single-mode Fabry-Pérot cavity where the trap was set in,and a particularly selected external laser pulse through Raman transitions,the interchange of the quantum features between the quantum light states and the quantized trap states occurs.This kind of quantum conversion can be used to prepare some nonclassical trap states in an ion trap as well as to measure the properties of initial nonclassical vibrational states.
文摘A scheme for the generation of a nonclassical Bose-Einstein condensate is proposed in a J_(g)=1→J_(e)=0 system where ultracold atoms are populated in one ground-state sublevel|g_〉and form a Bose-Einstein condensate.By coupling the condensate to copropagating classical(σ^(-))and quantum(σ^(+))non-resonant travelling-wave laser fields,effective two-photon excitations between two ground-state sublevels|g_〉and|g+〉create a new condensate in|g+〉.For an appropriate selection of the interaction time and atom-field coupling strengths,the quantum features of the quantized laser field,which may be prepared in a certain nonclassical state,can be exchanged with those of the quantum density field of the generated condensate.
基金supported by the National Natural Science Fundation of China(Grant No.61127014)the National Key Scientific Instrument Project(Grant No.2012YQ150092)
文摘A single-photon detector is an extremely sensitive device capable of registering photons,offering essential technical support for optics quantum information applications.We review herein our recent experimental progress in the development and application of single-photon detection techniques.Techniques based on advanced self-differencing,low-pass filtering,frequency up-conversion and photon-number-resolving are introduced for attaining high-speed,high-efficiency,low-noise single-photon detection at infrared wavelengths.The advantages of high-speed single-photon detection are discussed in some applications,such as the laser ranging and quantum key distribution.The photon-number-resolving detection is shown to support efficient quantum random number generation.
基金partly funded by the National Natural Science Foundation of China(Grant Nos.10525416,10804032,and 10990101)the National Basic Research Program of China(Grant No.2006CB806005)+1 种基金Projectsfrom Shanghai Science and Technology Commission(Grant Nos.08ZR1407100 and 09QA1402000)Shanghai Educational Development Foundation(Grant No.2008CG29)
文摘The molecular wake-assisted interaction between two collinear femotosecond laser pulses is investigated in air,which leads to the generation of a controllable 1.8 mJ super-continuum pulse with an elongated self-guided channel due to the cross-phase modulation of the impulsively aligned diatomic molecules in air.For two parallel launched femtosecond laser pulses with a certain spatial separation,controllable attraction and repulsion of the pulses are observed due to the counter-balance among molecular wakes,Kerr and plasma effects,where the molecular wakes show a longer interaction distance than the others to control the propagation of the intense ultrashort laser pulses.
