Circulating pulse cavity enhancement as a method for extreme momentum transfer atom interferometry

Abstract

Large-scale atom interferometers promise unrivaled strain sensitivity to mid-band gravitational waves, and will probe a new parameter space in the search for ultra-light scalar dark matter. These proposals require gradiometry with kilometer-scale baselines, a momentum separation above 104ℏk between interferometer arms, and optical transitions to long-lived clock states to reach the target sensitivities. Prohibitively high optical power and wavefront flatness requirements have thus far limited the maximum achievable momentum splitting. Here we propose a scheme for optical cavity enhanced atom interferometry, using circulating, spatially resolved pulses, and intracavity frequency modulation to meet these requirements. We present parameters for the realization of 20 kW circulating pulses in a 1 km interferometer enabling 104ℏk splitting on the 698 nm clock transition in 87Sr. This scheme addresses the presently insurmountable laser power requirements and is feasible in the context of a kilometer-scale atom interferometer facility.

Light-pulse atom interferometry with entangled atom-optical elements

“…Even though cavities with high finesse can drive Rabi cycles with low photon numbers, they are impractical for atom interferometry, where large separations and therefore large mode volumes are required. Nonetheless, cavity-based schemes are currently explored for atom interferometry [12][13][14][15][16], but they do not target a regime where quantization effects are observable. However, realizing three entangled fields adds another level of complexity.…”

“…This drive toward large spatial separations [47] is in conflict with the requirements of small mode volumes. Current developments of cavity-based atom interferometers [12][13][14][15][16] strive for a cleaner mode structure and higher intensities. However, there will be no application of such setups to a low-photon number regime in the foreseeable future.…”

“…These interferometers are implemented in a semi-classical manner, where beam splitters and mirrors are realized by diffraction from intense classical light pulses [11]. In light of the current drive towards optical cavity-based atom interferometers [12][13][14][15][16], we study the effect of quantized light fields generating the atom-optical elements [17], and we discuss scenarios in which they are entangled with each other.…”

Intra-Cavity Frequency-Doubled VECSEL System for Narrow Linewidth Rydberg EIT Spectroscopy

“…Moreover, such applications often simultaneously require laser linewidths narrower than the linewidth of the particular energy transition being manipulated. Laser cooling and trapping [1,2], largemomentum-transfer atom interferometry [3], high-fidelity Raman-mediated qubit gates [4], and Rydberg-atom electrometry [5,6] are examples of topics attracting considerable interest that would benefit from the availability of lower cost, higher power lasers with satisfactory spectral characteristics at these wavelengths [7]. Presently, the range of needs for such applications is met with complex systems including titanium-sapphire and amplified external-cavity diode (ECDL) lasers in combination with sum-frequency and second-harmonic generation.…”

Multi-photon Atom Interferometry via cavity-enhanced Bragg Diffraction

“…Such a response degrades the shape of the light pulses used to coherently manipulate the matter waves [28]. While these effects were considered, up to now, as a fundamental issue limiting the use of optical cavities for atom interferometry [26], novel schemes were recently proposed to circumvent this problem using light-shift engineering [29] and intracavity frequency modulation on circulating pulses [30]. To date, an experimental demonstration is of great interest to sweep the resonance of the 780 nm to generate our pulse across the width of the beam (see 4.2.2 for theory, and 4.3.2 for experimental results).…”