Fully reciprocal atomic interferometric gyroscope

Patent metadata

Field	Value
Publication number	US-10352702-B2
Application number	US-201715418990-A
Country	US
Kind code	B2
Filing date	Jan 30, 2017
Priority date	Sep 2, 2016
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

A fully reciprocal atomic interferometric gyroscope is provided. The fully reciprocal atomic interferometric gyroscope includes an atomic chamber, a plurality of lasers, a controller and measurement sensor. The atomic chamber is used to hold an atom cloud. The plurality of lasers are selectively positioned to selectively direct laser beams into the atomic chamber. The controller is configured to control the plurality lasers to initially cool the atom cloud to a point where at least one optical lattice can be formed that is used to move wave function halves of atoms of the atom cloud along split wave function paths that form an interferometer cycle. The measurement sensor is configured to conduct a phase readout of a wave function upon the completion of at least one interferometer cycle around the split wave function paths.

First claim

What is claimed is:

1. A method of forming a fully reciprocal atomic interferometric gyroscope, the method comprising:
cooling atoms of an atomic cloud held in a chamber;
splitting each atom into a first atomic wave function half and a second atomic wave function half at a point of separation;
using at least one optical lattice to move the first atomic wave function half along a first split wave function path and the second atomic wave function half along a second split wave function path in a first direction along a plane that is transverse to a rotation axis along which rotation sensing is desired;
causing the first split wave function path and the second split wave function path to intersect with each other to complete a first half of an interferometer cycle a select distance from the point of separation;
using the at least one optical lattice to at least in part move the first atomic wave function half along the second split wave function path and the second atomic wave function half along the first split wave function path in a second direction along the plane back to the point of separation to complete an interferometer cycle; and
conducting a phase readout after at least one complete interferometer cycle.

2. The method of claim 1 , further comprising:
implementing a pair of overlapping optical lattices to control a separation distance of the first split wave function path from the second split wave function path.

3. The method of claim 2 , wherein implementing the pair of overlapping optical lattices to control the separation distance of the first split wave function path from the second split wave function path further comprises:
directing a first laser beam of frequency f 0 in a first direction into the atom cloud and a second laser beam of an offset frequency f 0 −δ 2 and a third laser beam of an offset f 0 +δ 2 in an opposite direction into the atom cloud.

4. The method of claim 1 , wherein cooling the atoms of the atom cloud held in the chamber, further comprises:
cooling the atoms to a point where a velocity spread of the atoms is less than a velocity imparted to an atom by a scattering event with a photon.

5. The method of claim 1 , wherein the cooling of atoms of the atom cloud further comprises:
applying a plurality of lasers at a select frequency to cool and trap the atoms using at least one of a magneto-optical trap, optical molasses, Raman cooling and Raman velocity selection.

6. The method of claim 1 , wherein splitting each atom into a first atomic wave function half and a second wave function half at the point of separation further comprises:
placing each atom in a superposition of two momentum states.

7. The method of claim 6 , wherein placing each atom in a superposition of two momentum states further comprises:
flashing at least one of the at least one optical lattice with at least one of a half of a Bragg pulse and a Raman pulse.

8. The method of claim 1 , further comprising:
conducting a plurality of altered cooling cycles and measurement cycles.

9. A method of forming a fully reciprocal atomic interferometric gyroscope, the method comprising:
cooling atoms of an atom cloud held in a chamber until an optical lattice can be formed;
using a first optical lattice to move an atomic wave function of atoms of the cooled atom cloud in a first direction along a plane that is transverse to a rotational axis along which rotation sensing is desired;
splitting each atom into a first atomic wave function half and a second wave function half at a point of separation;
using a pair of overlapping second optical lattices to control a separation distance of the first atomic wave function half from the second wave function half so the first atomic wave function half travels along a first split wave function path and the second wave function half travels along a second wave function path in the first direction;
using the pair of overlapping second optical lattices to cause the first split wave function path and the second wave function path to intersect to complete a first half of an interferometer cycle at an intersection point that is a select distance from the point of separation;
upon reaching the intersection point, using the first optical lattice to change movement of the first atomic wave function half and the second atomic wave function half in a second direction that is opposite the first direction and using the pair of overlapping second optical lattices to cause the first atomic wave function half to move along the second split wave function path and the second atomic wave function half to move along the first split wave function path back to the point of separation to complete an interferometer cycle; and
conducting a phase readout.

10. The method of claim 9 , wherein splitting each atom into a first atomic wave function half and a second atomic wave function half at the point of separation further comprises:
placing each atom in a superposition of two momentum states by flashing the pair of overlapping second optical lattices with a half of a Bragg pulse to cause each atom to diffract from an optical intensity grating with half of the atomic wave function being placed into a plus two recoil state and the other half of the atomic wave function being placed in a minus two recoil state.

11. The method of claim 9 , wherein implementing the pair of overlapping second optical lattices to control a separation distance of the first atomic wave function half from the second wave function half further comprises:
directing a first laser beam of a first frequency along the plane in a third direction into the atom cloud and directing a second laser beam of the first frequency minus a small frequency shift and a third laser beam of the first frequency plus a small frequency shift along the plane in a fourth direction that is opposite the third direction of the first laser beam into the atom cloud.

12. The method of claim 9 , wherein using the first optical lattice to move the atomic wave function of atoms of the cooled atom cloud in the first direction further comprises:
directing a first laser beam having a frequency of f 0 +δ 2 in a first direction into the atom cloud and a second laser beam having a frequency of f 0 −δ 2 in a second opposite direction into the atom cloud, and
wherein using the first optical lattice to change movement of the first atomic wave function half and the second atomic wave function half in the second direction that is opposite the first direction further includes,
changing the frequency of the first laser beam to f 0 −δ 2 and the second laser beam to f 0 +δ 2 .

Assignees

• Honeywell Int Inc

Inventors

• Compton Robert

Classifications

• G01C19/64 Primary

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