Thermal rubidium atomic beam source using a glass capillary plate for inertial navigation with atom interferometers

Atom-interferometer–based inertial sensors using a thermal atomic beam [1] are among the most promising candidates for inertial navigation, as they offer high bandwidth and dead-time-free operation. Recently, we have proposed a new scheme for a thermal atomic beam inertial sensor that enables a wide dynamic range and simultaneous absolute measurements of acceleration and rotation [2]. To realize this scheme, it is crucial to develop a high-flux, well-collimated, and highly controllable thermal atomic beam.

We have developed a thermal atomic beam source for rubidium atoms employing a glass capillary plate with a high length-to-diameter (L/D) ratio to ensure excellent beam collimation. Using a glass capillary plate with an L/D ratio of 1000 (1 mm thickness and 1 μm capillary diameter , and an open-area ratio of 30%), we successfully obtained a thermal atomic beam with a flux comparable to that of a conventional thermal source. The measured fluorescence image obtained by illuminating the atomic beam with probe light resonant to the atomic transition agrees with theoretical calculations that take into account the capillary geometry and Doppler broadening. The estimated transverse velocity width indicates that our atomic beam source provides sufficient collimation for implementing the closed-loop interferometric scheme proposed in Ref. [2].

[1] T. L. Gustavson et al., Class. Quantum Grav. 17, 2385 (2000).

[2] T. Sato et al., arXiv:2509.05942 (2025).