We propose a scheme to significantly enhance the sensitivity of atom interferometry performed with Bose-Einstein condensates. When an optical two-photon Raman transition is used to split the condensate into two modes, some information about the number of atoms in one of the modes is contained in one of the optical modes. We introduce a simple model to describe this process, and find that by processing this information in an appropriate way, the phase sensitivity of atom interferometry can be enhanced by more than a factor of 10 for realistic parameters.
We propose and demonstrate a scheme to enable Doppler compensation within optical cavities for atom interferometry at significantly increased mode diameters. This has the potential to overcome the primary limitations in cavity enhancement for atom interferometry, circumventing the cavity linewidth limit and enabling mode filtering, power enhancement, and a large beam diameter simultaneously. This approach combines a magnified linear cavity with an intracavity Pockels cell. The Pockels cell introduces a voltage tunable birefringence allowing the cavity mode frequencies to track the Raman lasers as they scan to compensate for gravitationally induced Doppler shifts, removing the dominant limitation of current cavity enhanced systems. A cavity is built to this geometry and shown to simultaneously realize the capability required for Doppler compensation, with a 5.04~mm
1/e2 diameter beam waist and an enhancement factor of $>$5x at a finesse of 35. Furthermore, this has a tunable Gouy phase, allowing the suppression of higher order spatial modes and the avoidance of regions of instability. This approach can therefore enable enhanced contrast and longer atom interferometry times while also enabling the key features of cavity enhanced atom interferometry, power enhancement and the reduction of aberrations. This is relevant to future reductions in the optical power requirement of quantum technology, or in providing enhanced performance for atom interferometers targeting fundamental science.
We propose and demonstrate a scheme for Doppler compensated optical cavity enhancement of atom interferometers at significantly increased mode diameters. This overcomes the primary limitations in cavity enhancement for atom interferometry, circumventing the cavity linewidth limit and enabling spatial mode filtering, power enhancement, and a large beam diameter simultaneously. This approach combines a magnified linear cavity with an intracavity Pockels cell. The Pockels cell induces a voltage-controlled birefringence allowing the cavity mode frequencies to follow the Raman lasers as they track gravitationally induced Doppler shifts, removing the dominant limitation of current cavity enhanced systems. A cavity is built to this geometry and shown to simultaneously realise Doppler compensation, a 5.8 ± 0.15 mm1/ e 2 diameter beam waist and an enhancement factor of >5× at a finesse of 35. Tuneable Gouy phase enables the suppression of higher order spatial modes and the avoidance of regions of instability. Atom interferometers will see increased contrast at extended interferometry times along with power enhancement and the reduction of optical aberrations. This is relevant to power constrained applications in quantum technology, alongside the absolute performance requirements of fundamental science.