Multiple-cavity vapor cell structure for micro-fabricated atomic clocks, magnetometers, and other devices

1. An apparatus comprising:

a vapor cell having:

a first cavity configured to receive a first material;

a second cavity fluidly connected to the first cavity by a first channel, the second cavity configured to receive one or more gases dissociated from the first material and allow radiation to pass through; and

a third cavity fluidly connected to one of the first cavity or the second cavity by a second channel, the third cavity configured to receive a second material for absorbing a portion of the one or more gases dissociated from the first material.

2. The apparatus of claim 1 , wherein the vapor cell includes a first wafer defining the first, second, and third cavities and the first and second channels.

3. The apparatus of claim 2 , wherein the vapor cell includes a second wafer secured to the first wafer, the second wafer sealing ends of the first, second, and third cavities and the first and second channels.

4. The apparatus of claim 2 , wherein the vapor cell includes a second wafer secured to the first wafer, the second wafer thinner than the first wafer at a location proximate to the first cavity.

5. The apparatus of claim 1 , wherein:

the first material comprises an alkali-based material able to dissociate into a metal vapor and a buffer gas; and

the second material comprises a getter material able to absorb at least a portion of the buffer gas.

6. The apparatus of claim 5 , wherein:

the first material comprises cesium azide (CsN 3 ) able to dissociate into cesium vapor and nitrogen gas (N 2 ); and

the second material comprises a zirconium-based alloy.

7. A system comprising:

a vapor cell including:

a first cavity configured to receive a first material;

a second cavity fluidly connected to the first cavity by a first channel, the second cavity configured to receive one or more gases dissociated from the first material and allow radiation to pass through; and

a third cavity fluidly connected to one of the first cavity or the second cavity by a second channel, the third cavity configured to receive a second material for absorbing a portion of the one or more gases dissociated from the first material; and

an illumination source configured to direct radiation through at least one of the first, second, or third cavity.

8. The system of claim 7 , wherein the vapor cell includes a first wafer defining the first, second, and third cavities and the first and second channels.

9. The system of claim 8 , wherein the vapor cell includes a second wafer secured to the first wafer, the second wafer sealing ends of the first, second, and third cavities and the first and second channels.

10. The system of claim 8 , wherein the vapor cell includes a second wafer secured to the first wafer, the second wafer thinner than the first wafer at a location proximate to the first cavity.

11. The system of claim 7 , further comprising:

a clock generation circuitry configured to generate a clock signal based on the radiation directed through the second cavity.

12. The system of claim 7 , further comprising:

a magnetic field calculator configured to determine a measurement of a magnetic field through the vapor cell based on the radiation directed through the second cavity.

13. A method for use in a vapor cell having multiple cavities fluidly connected by one or more channels, the method comprising:

placing a first material into a first cavity of a first wafer before the first cavity is sealed;

placing onto a second wafer a second material including a getter material;

securing the second wafer to the first wafer to partially seal the first cavity and at a temperature that activates the getter material;

dissociating a portion of the first material into one or more gases that are contained within the vapor cell; and

absorbing a portion of the one or more gases using the second material.