Theoretical analysis of aliasing noises in cold atom Mach-Zehnder interferometers

Abstract

Abstract. We present a theoretical analysis of aliasing noises that might appear in cold atom Mach-Zehnder interferometers used for the measurement of various physical quantities. We focus more specifically on single cold atom gyroscopes. To evaluate the level of aliasing noises, we have developed a model based on the power spectral densities of the different identified noise sources as input parameters and which makes use of a servo-loop to realize a precise measurement of the rotation rate. The model allows one to take into account different modes of operation, like a continuous as well as a pulsed or even a multi-ball operation. For monokinetic atoms, we show that the intermodulation noise can be completely filtered out with a continuous mode of operation and an optimum modulation scheme for any modulation frequency but also with a pulsed operation however only for specific launching frequencies. In the case of a real continuous atomic beam having a velocity distribution, it comes out that a high attenuation can be reached which indicates clearly the potential stability improvement that can be expected from a continuous operation.

A continuous, sub-Doppler-cooled atomic beam interferometer for inertial sensing

“…The phase readout methods demonstrated herein are amenable to operation in dynamic environments: lock-in detection with f R >= (2T ) −1 allows for changes in inertial signal at frequencies up to the first zero in the interferometer's transfer function [42], while phase shear readout at high rate in real time is possible through the use of optical intensity masks combined with single-pixel imaging, or else linear overlap integral computation in a fast processor rather than nonlinear curve fitting. Finally, a large number of techniques for hybrid [6,7], closed-loop [24], or composite-fringe [37] interferometer operation have been developed to extend dynamic range and are applicable to continuous cold-beam interferometry.…”

“…These continuous-beam, or "spatialdomain," interferometers largely eliminate the need for timevarying optical signals and magnetic fields, simplifying control electronics and electro-optics compared with time-domain measurements. Advantages in the noise response of continuous atom interferometers has been demonstrated theoretically [24]. Gaussian pulse shaping, which occurs automatically in spatial-domain interferometers with Gaussian laser beams, also has advantages in rejection of high-frequency phase noise [25].…”

Three-Dimensional Cooling of an Atom-Beam Source for High-Contrast Atom Interferometry

“…Compared with hot-atom beam sources, the slower mean velocity and narrower velocity distribution of cold atom beams both increase the interrogation time T and increase the fringe contrast of atom interferometers and clocks, resulting in improved measurement sensitivity [5][6][7]. Cold-atom sensors that operate periodically rather than continuously can undersample signals and noise, leading to the Dick effect in clocks [8] and inertial navigation errors for accelerometers and gyroscopes [9][10][11][12][13].…”