arXiv subjects

R. Caldani

Publications and source records attributed to R. Caldani.

3 recordsLinked to original sources

arXiv2025

Temporal dynamics in the Bragg reflection of light by cold atoms: flash effect and superradiant decay

We study the temporal dynamics of light interacting with a one-dimensional lattice of cold atoms. In such a system, a photonic band gap opens up, yielding an efficient Bragg reflection for an incident field incoming with the right angle and detuning. Here, we report two new effects appearing in the Bragg reflection. First, for some detunings, there is a ``flash'', i.e., a transient increase of the reflected intensity when the incident field is switched off. Second, the subsequent extinction of the reflected field is clearly superradiant, with decay rates up to height times the natural decay rate of the atomic excited state. Numerical simulations are in qualitative agreement with the observations, which can be explained by a classical photonic model. Our results are a step towards exploiting this photonic band gap in atomic systems for quantum-optical applications.

physics.atom-ph↗

arXiv2018

Simultaneous accurate determination of both gravity and its vertical gradient

We present a method for the accurate measurements of both the gravity acceleration and its vertical gradient using a dual atom interferometer, in principle free from any uncertainty related to the absolute or relative positions of the two atomic samples. The method relies on the use of a dual lock technique, which stirs simultaneously the chirp rate applied to the frequency difference between the interferometer lasers to compensate the gravity acceleration, and the frequency jump applied to the lasers at the mid pulse of the interferometer to compensate for the gravity gradient. This allows in the end to determine the two inertial quantities of interest in terms of frequencies.

physics.atom-ph↗

arXiv2017

Differential phase extraction in dual interferometers exploiting the correlation between classical and quantum sensors

We perform the experimental demonstration of the method proposed in [Phys. Rev. A 91, 063615 (2015)] to extract the differential phase in dual atom interferometers. From a single magneto-optical trap, we generate two atomic sources, vertically separated and free-falling synchronously, with the help of an accelerated lattice. We drive simultaneous Raman interferometers onto the two sources, and use the correlation with the vibration signal measured by a seismometer to extract the phase of each interferometer. We demonstrate an optimal sensitivity of the extracted differential phase between the two interferometers, free from vibration noise and limited by detection noise, when the two interferometers are in phase.

physics.atom-ph↗