Closed-loop dual-atom-interferometer inertial sensor with continuous cold atomic beams

We demonstrate a closed-loop light-pulse atom-interferometer inertial sensor that can realize continuous decoupled measurements of acceleration and rotation rate. The sensor operates with double-loop atom interferometers, which share the same Raman light pulses in a spatially separated Mach-Zehnder configuration and use continuous cold atomic beams propagating in opposite directions from two ${\text{2D}}^{+}$ magneto-optical trappings. Acceleration and the rotation rate are decoupled and simultaneously measured by the sum and difference of dual-atom-interferometer signals, respectively. The sensitivities of inertial measurements are also increased to be approximately 1.86 times higher than that of a single atom interferometer. The acceleration phase shift is compensated in real time by phase locking these interferometers via the Raman laser phases from the sum-interferometer signal, and the gyroscope performance is improved. We achieve long-term stabilities of $6.1\text{μ}\text{g}$ and 840 nrad/s for the acceleration and the rotation rate, respectively, using a short interrogation time of 0.87 ms (interference area $A=0.097{\text{mm}}^2$). This work provides a building block for an atomic interferometer-based inertial measurement unit for use in field applications that require a high data rate and high stability.