Contrast enhancement via shaped Raman pulses for thermal cold atom cloud interferometry

Optimal control of mirror pulses for cold-atom interferometry

“…The two-level system hence consists of the states |1, p and |2, p +hk L , where 1 and 2 refer to the two atomic states andhk L is the photon impulse. If the beams are kept resonant at the center of the velocity distribution, e.g., by chirping the frequency to account for acceleration under gravity [1,14], the detuning can be written as |k L |v, where v is the relative speed of a given atom along the direction of the wave vector. Therefore, the detuning of a given atom will remain approximately fixed throughout the interferometer sequence, and the range of detunings will be due to the momentum distribution and hence temperature of the cloud.…”

“…the form of the propagator for a pulse with a constant field vector and duration t is given by [14,28]…”

“…Various techniques have been developed in the field of nuclear magnetic resonance (NMR) spectroscopy to produce control pulses that are robust to variations in the interaction strength and detuning, and such techniques should be applicable to other systems, including the effective two-level schemes of atom interferometry. Shaped pulses [13][14][15], rapid adiabatic pulses [16][17][18], and composite pulses [19][20][21][22] all use complex time-dependent interactions to reproduce the desired operation of a single pulse while compensating for the effects of inhomogeneities. For atom interferometry, McGuirk et al [10] suggested that composite pulses could improve the augmentation pulses within large momentum transfer (LMT) arrangements, and Butts et al [12] demonstrated that the WALTZ [23] composite inversion pulse doubled the sensitivity of a cold Cs atom interferometer.…”

Improving the phase response of an atom interferometer by means of temporal pulse shaping

“…In addition to the rectangular and Gaussian pulses, we discuss two other representative pulse shapes: (i) the GSinc pulse, which is the product of a Gaussian and a cardinal sine, and (ii) the Gaussian-Flat pulse (labeled GFlat thereafter) which is a flat pulse with Gaussian edges. For completeness of the presentation, we study in section 4 the influence of pulse shaping on the frequency selectivity, in line with previous works [26,27]. Finally, we present in section 5 a correction to the interferometer scale factor associated with pulse shaping, and discuss its relevance for different precision measurements involving AI based sensors.…”

“…Efficient transitions (i.e. high contrasts) can thus be achieved by temporally shaping the pulse intensity and phase, as shown in [26,27]. Moreover, when driving an interferometer with large momentum transfer (LMT) atom optics, it has been shown that pulses of Gaussian temporal shape significantly improve the transfer efficiency with respect to rectangular pulse shapes [28,29].…”