An atomic beam is irradiated with a first laser beam, a second laser beam, and a third laser beam. The first laser beam and the third laser beam each have a wavelength corresponding to a transition between a ground state and a first excited state. The second laser beam has a wavelength corresponding to a transition between the ground state and a second excited state. First, atoms each having a smaller velocity component than a predetermined velocity in a direction orthogonal to the traveling direction of the atomic beam are changed from the ground state to the first excited state by the first laser beam. Subsequently, a momentum is provided for individual atoms in the ground state by the second laser beam, which removes the atoms from the atomic beam. Finally, atoms in the first excited state are returned from the first excited state to the ground state by the third laser beam.

Systems and methods for dynamic optical interferometer locking using entangled photons are provided. In certain embodiments, a system includes an optical source for generating a pair of photons. Also, the system includes first and second emitter/receivers that emit first and second photons towards first and second remote reflectors and receive reflected first and second photons along first and second optical paths. Additionally, the system includes a mode combiner for combining the reflected first photon and second photon into a first and second output port. Moreover, the system includes a coarse adjuster that performs coarse adjustments and a fine adjuster that performs fine adjustments to the first and second optical paths. Further, the system includes a plurality of photodetectors that detect photons from the first and second output ports. Additionally, the system includes a processor that controls the coarse and fine adjustments based on received signals from the photodetectors.

The present application discloses a control method for fast trapping and high-frequency mutual ejection of cold atom groups. The control method includes: arranging three groups of optical stops on three groups of light sources (splitters) in three-dimensional magneto-optical traps, to form a shaded regions; ejecting a cold atom group from the first three-dimensional magneto-optical trap along a movement trajectory to the second three-dimensional magneto-optical trap, where the movement trajectory passes through the shaded regions of the two three-dimensional magneto-optical traps; and, when it is determined that the cold atom group enters the shaded region of the first three-dimensional magneto-optical trap, trapping a next cold atom group by turning on three-dimensional cooling light and three-dimensional repumping light in the first three-dimensional magneto-optical trap.

Systems and methods for direct measurement of imbalanced optical paths using entangled photons are provided. A system includes an optical source for generating a pair of simultaneously produced photons. The system also includes first and second emitter/receivers that emit first and second photons in the pair of simultaneously produced photons towards a first and second remote reflector and receives the reflected first and second photons along first and second optical paths. Further, the system includes a mode combiner for combining the reflected first and second photons into first and second output ports. Moreover, the system includes photodetectors that detect photons from the first and second output ports. Also, the system includes a processor that measures a difference in time delay between the first and second optical paths based on a time difference of arrival of signals from the photodetectors.

The present application relates to an atom interferometry method. The atom interferometry method releases atoms from an atom source into an interferometer region. Pulses of light are then directed at the atoms to place the atoms in different quantum states and to recombine the quantum states such that the recombined quantum states interfere with each other when the quantum states are overlapped spatially. The recombined quantum states creates a spatial fringe pattern with a phase. The spatial fringe pattern and the phase of the spatial fringe pattern are detected when the quantum states are overlapped spatially. The overlapped spatial fringe pattern is then used to measure physical quantities such as local gravity, the gravitational constant, the fine structure constant, the ratio of Planck's constant to the atomic mass, rotation of the atom interferometer, acceleration of the atom interferometer, and the like.

Systems and methods for direct measurement of imbalanced optical paths using entangled photons are provided. A system includes an optical source for generating a pair of simultaneously produced photons. The system also includes first and second emitter/receivers that emit first and second photons in the pair of simultaneously produced photons towards a first and second remote reflector and receives the reflected first and second photons along first and second optical paths. Further, the system includes a mode combiner for combining the reflected first and second photons into first and second output ports. Moreover, the system includes photodetectors that detect photons from the first and second output ports. Also, the system includes a processor that measures a difference in time delay between the first and second optical paths based on a time difference of arrival of signals from the photodetectors.

Systems and methods for dynamic locking of optical path times using entangled photons are provided. A system includes an optical source for generating bi-photons; tracer laser beam sources for generating tracer laser beams; telescopes that emit the tracer laser beams and the bi-photons to remote reflectors, each bi-photon traveling along an optical path in a pair of optical paths toward a corresponding remote reflector, wherein the telescopes receive reflected bi-photons from the remote reflectors; and communication links, wherein the optical source respectively communicates with first and second remote reflectors through a first and second communication link. Also, the optical source uses the tracer laser beams and the communication links to respectively point the bi-photons towards the remote reflectors. Moreover, the system includes an interferometer that provides information regarding detection of the reflected bi-photons, wherein the optical source uses the information to adjust optical path lengths to be substantially equal.

The present application relates to an atom interferometry method. The atom interferometry method releases atoms from an atom source into an interferometer region. Pulses of light are then directed at the atoms to place the atoms in different quantum states and to recombine the quantum states such that the recombined quantum states interfere with each other when the quantum states are overlapped spatially. The recombined quantum states creates a spatial fringe pattern with a phase. The spatial fringe pattern and the phase of the spatial fringe pattern are detected when the quantum states are overlapped spatially. The overlapped spatial fringe pattern is then used to measure physical quantities such as local gravity, the gravitational constant, the fine structure constant, the ratio of Planck's constant to the atomic mass, rotation of the atom interferometer, acceleration of the atom interferometer, and the like.

A method for identifying three entangled photons includes generating a set of first, second, and third entangled photons correlated in time and interfering the first and second entangled photons based on a difference between a first optical path from an output of an optical source that generates the first entangled photon to a first optical input to an interferometric beam splitter and a second optical path from an output of the optical source that generates the second entangled photon to a second input of the interferometric beam splitter. A first electrical signal is generated in response to detection of a first photon generated by the interfering of the first and second entangled photons. A second electrical signal is generated in response to detection of a second photon generated by the interfering of the first and second entangled photons. A third electrical signal is generated in response to detection of the third entangled photon. The first photon coincidence is determined from the first, second and their electrical signals, thereby identifying three entangled photons.

Systems and methods for dynamic locking of optical path times using entangled photons are provided. A system includes an optical source for generating bi-photons; tracer laser beam sources for generating tracer laser beams; telescopes that emit the tracer laser beams and the bi-photons to remote reflectors, each bi-photon traveling along an optical path in a pair of optical paths toward a corresponding remote reflector, wherein the telescopes receive reflected bi-photons from the remote reflectors; and communication links, wherein the optical source respectively communicates with first and second remote reflectors through a first and second communication link. Also, the optical source uses the tracer laser beams and the communication links to respectively point the bi-photons towards the remote reflectors. Moreover, the system includes an interferometer that provides information regarding detection of the reflected bi-photons, wherein the optical source uses the information to adjust optical path lengths to be substantially equal.