Patent ID: 9575144
Date: 2017-02-21
CPC Classifications: G01R

Claim:
1. An apparatus, comprising: an optical interface to accept a first light having a predetermined state of linear polarization; a pump light source to produce a pump light having circular polarization; a vapor cell comprising a sealed vessel containing an alkali-metal gas, the vapor cell further comprising a first input port to receive the first light, a second input port to accept the pump light from a direction perpendicular to the first light, and an output port configured to produce a second light; an electromagnetic source configured to apply an electromagnetic field to the vapor cell at a direction perpendicular to the first light and perpendicular to the pump light; a second linear polarizer, having an axis of polarization perpendicular to the predetermined state of linear polarization of the first light, the second polarizer configured to receive the second light and to produce a third light; and a photodetector configured to receive the third light, to produce an intensity measurement of the third light, wherein the output port of the vapor cell comprises the input port of the vapor cell for the first light.