Optical lattice clock, clock device and laser light source

Patent metadata

Field	Value
Publication number	US-9553597-B2
Application number	US-201314422177-A
Country	US
Kind code	B2
Filing date	Aug 12, 2013
Priority date	Aug 17, 2012
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

Various embodiments improve accuracy by increasing the number of atoms engaged in a clock transitions in an optical lattice clock. An exemplary optical lattice clock an embodiment comprises an optical waveguide, an optical path, a laser light source, and a laser cooler. The optical path has a hollow pathway that extends from a first end to a second end while being surrounded with a tubular wall, which is used as a waveguide path. The optical path passes between mirrors and through the pathway. The laser light source supplies to the optical path a pair of lattice lasers (L 1 and L 2 ) propagating in opposite directions with each other. The laser cooler supplies cooled atoms that have two levels of electronic states associated with a clock transition to the vicinity of the first end of the optical waveguide.

First claim

What is claimed is:

1. A system comprising:
an optical lattice clock including:
an atom feeder configured to supply atoms having two levels of electronic states for clock transitions;
a laser light source configured to form a one dimensional optical lattice made of a standing wave having a selected wavelength, the selected wavelength being a wavelength that generates a mutually identical amount of light-shift for each of the two levels, and the optical lattice being a moving lattice of the standing wave; and
an optical waveguide having a hollow pathway surrounded by a tubular wall, the optical lattice being formed in the hollow pathway, the atoms being trapped by the optical lattice formed in the hollow pathway, wherein the optical waveguide has a first end and a second end, the hollow pathway extends from the first end to the second end, the laser light source forms the optical lattice in the hollow pathway by supplying a first lattice laser propagating in a first direction and a second lattice laser propagating in a second direction that is opposite to the first direction, and the optical lattice is the moving lattice of the standing wave that moves from the first end to the second end while trapping the atoms, the atoms making the clock transitions while being transported by the moving lattice through the hollow pathway; and
a clock device configured to use light of the selected wavelength for a frequency reference, the light being absorbed or emitted by the clock transitions.

2. The system according to claim 1 , wherein the optical lattice clock further includes a laser cooler configured to cool and supply the atoms into a vicinity of the first end of the optical waveguide for introducing the atoms into the hollow pathway at the first end.

3. The system according to claim 1 wherein the selected wavelength is a magic wavelength.

4. An optical lattice clock comprising:
an atom feeder configured to supply atoms having two levels of electronic states for clock transitions;
a laser light source configured to form a one dimensional optical lattice of a standing wave having a selected wavelength, the selected wavelength being a wavelength that generates a mutually identical amount of light-shift for each of the two levels; and
an optical waveguide having a hollow pathway surrounded by a tubular wall, the optical lattice being formed in the hollow pathway, the atoms being trapped by the optical lattice formed in the hollow pathway;
wherein the optical waveguide has a first end and a second end, the hollow pathway extends from the first end to the second end, the laser light source forms the optical lattice of the standing wave in the hollow pathway by supplying a first lattice laser propagating in a first direction and a second lattice laser propagating in a second direction that is opposite to the first direction, and the optical lattice is a moving lattice of the standing wave that moves from the first end to the second end while trapping the atoms, the atoms making the clock transitions while being transported by the moving lattice through the hollow pathway.

5. The optical lattice clock according to claim 4 , wherein the optical lattice clock further includes a laser cooler configured to cool and supply the atoms into a vicinity of the first end of the optical waveguide for introducing the cooled atoms into the hollow pathway at the first end, the cooled atoms to be trapped and transported by the moving lattice through the hollow pathway.

6. The optical lattice clock according to claim 4 , wherein the optical waveguide is a hollow core photonic crystal fiber (HC-PCF) having a hollow core, and the hollow pathway of the optical waveguide is a pathway formed by the hollow core of the HC-PCF.

7. The optical lattice clock according to claim 4 , wherein the atoms are introduced into the hollow pathway at the first end at a feed rate such that a total number of the atoms between the first end and the second end of the optical waveguide is greater than or equal to a predetermined value.

8. The optical lattice clock according to claim 4 , further comprising a ring resonator having an optical path, the ring resonator configured to use the hollow pathway for at least a part of the optical path, wherein the moving lattice is formed with the standing wave obtained by shifting frequencies of the pair of lattice lasers, and openings of the hollow pathway at the first end and the second end are irradiated by the pair of lasers to be supplied for the ring resonator.

9. The optical lattice clock according to claim 4 wherein the selected wavelength is a magic wavelength.

10. An optical lattice clock comprising:
an optical waveguide having a hollow pathway surrounded with a tubular wall for its waveguide path, the hollow pathway extending from a first end to a second end; and
a laser light source that forms an optical lattice made of a standing wave by supplying a pair of lattice lasers, each of the lattice lasers propagating in opposite direction with each other in the hollow pathway, the optical lattice being a one dimensional optical lattice of a selected wavelength that generates a mutually identical amount of light-shift for each of two levels of electronic states of atoms, and the optical lattice being a moving lattice of the standing wave moving from the first end to the second end while trapping the atoms,
wherein the optical lattice clock uses the two levels of the electronic states of the atoms that are transported by the moving lattice through the hollow pathway for clock transitions.

11. The optical lattice clock according to claim 10 further comprising: a laser cooler configured to cool the atoms for supplying cooled atoms into a vicinity of the first end of the optical waveguide for introducing the cooled atoms into the hollow pathway at the first end.

12. The optical lattice clock according to claim 11 , wherein the cooled atoms are polarized or excited before entering into the first end.

13. The optical lattice clock according to claim 10 , wherein the optical waveguide is a hollow core photonic crystal fiber (HC-PCF), and wherein the hollow pathway of the optical waveguide is a pathway formed by a hollow core of the HC-PCF.

14. The optical lattice clock according to claim 10 , wherein the atoms are to become spin polarized fermions.

15. The optical lattice clock according to claim 10 , wherein the optical waveguide is configured in such a manner that inner diameter of the hollow pathway is greater than or equal to a minimum inner diameter, and wherein the minimum inner diameter makes interaction of the atoms with the tubular wall surrounding the hollow pathway weaker than a predetermined value.

16. The optical lattice clock according to claim 10 , wherein a feed rate of the atoms is such that a total number of atoms between the first end and the second end formed by the hollow pathway of the optical waveguide is greater than or equal to a predetermined value.

17. The optical lattice clock according to claim 10 , wherein the optical lattice clock uses light for a frequency reference, and wherein the light is to be absorbed due to the clock transitions between the two levels of the electronic states of the atoms positioned in the hollow pathway.

18. The optical lattice clock according to claim 10 , further comprising:
a ring resonator configured to utilize the hollow pathway for a part of its optical path, wherein the moving lattice is moved by shifting frequencies of the pair of lattice lasers, and openings of the hollow pathway at the first end and the secon

Assignees

• Riken

Inventors

• Katori Hidetoshi

Classifications

• H03L7/26 Primary

  using energy levels of molecules, atoms, or subatomic particles as a frequency reference · CPC title

• G04F5/14 Primary

  using atomic clocks · CPC title

• H01S3/06791

  Fibre ring lasers (fibre laser gyrometers G01C19/72) · CPC title