Cold Atom Interferometry

An atom interferometer comprising:

• a. an ensemble of atoms successively launched between a pair of magneto-optical traps;
• b. a plurality of pairs of counterpropagating laser beams traversing the ensemble of atoms for probing quantum states characterizing the atoms;
• and
• c. a beam-splitting surface common to the plurality of counterpropagating beam pairs, configured to reflect a portion of each of plurality of counterpropagating beam pair;
• d. a reflector for redirecting one of each pair of counterpropagating laser beams to form an interference pattern with the other of each pair of counterpropagating laser beams;
• and
• e. a detector configured to detect the interference pattern and generate a detector signal;
• and
• f. a processor for receiving the detector signal and deriving a measure of at least of relative phase and relative spatial alignment of each pair of counterpropagating laser beams.

An atom interferometer comprising:

• a. an ensemble of atoms successively launched between a pair of magneto-optical traps;
• b. a first plurality of laser beams, all characterized by a first Raman frequency, traversing the ensemble of atoms in a first set of parallel directions for probing quantum states characterizing the ensemble of atoms;
• c. a second plurality of laser beams, all characterized by a second Raman frequency, traversing the ensemble of atoms in a second set of parallel directions substantially counterpropagating with respect to the first set of parallel directions;
• d. a first fiber collimator for coupling the first laser beam from optical fiber to free-space propagation substantially parallel to a baseplate;
• e. a first parallel displacement beam splitter for splitting the first laser beam into a plurality of parallel beam paths;
• f. a second fiber collimator for coupling the second laser beam from optical fiber to free-space propagation substantially parallel to the baseplate;
• g. a beam-turning optic for steering the second laser beam in a path substantially parallel to the baseplate and substantially parallel to the plurality of parallel beam paths traversed by the first laser beam;
• h. a reflector for turning the second laser beam into a direction substantially antiparallel to the plurality of parallel beam paths traversed by the first laser beam;
• and
• i. a second parallel displacement beam splitter for splitting the second laser beam into a plurality of parallel beam paths each counterpropagating on the plurality of parallel beam paths traversed by the first laser beam.

An improvement to an atom interferometer having a first and a second magneto-optical trap (MOT) displaced with respect to each other by an inter-trap distance bisected by a center displaced from either MOT by a “center-to-trap distance,” with

• substantially orthogonal blue-detuned cooling beams traversing a first MOT in directions substantially opposing directions in which another pair of substantially orthogonal blue-detuned cooling beams traverse a second MOT, and
• substantially orthogonal red-detuned cooling beams traversing the first MOT in directions substantially opposing directions in which another pair of substantially orthogonal red-detuned cooling beams traverse the second MOT,
• wherein the improvement comprises:
• a. a first fiber collimator for coupling a first laser beam from optical fiber to free-space propagation in a first laser direction substantially parallel to a baseplate and displaced from the center by the center-to-trap distance;
• b. a second fiber collimator for coupling a second laser beam from optical fiber to free-space propagation substantially parallel to the baseplate, substantially orthogonal to the first laser direction, and also displaced from the center by the center-to-trap distance;
• c. a first pentaprism, disposed entirely within a sphere of radius no greater than three times the inter-trap distance about the center, for splitting the first laser beam into two orthogonal cooling beams;
• and
• d. a second pentaprism, disposed entirely within the sphere of radius no greater than three times the inter-trap distance about the center, for splitting the second laser beam into two orthogonal cooling beams.