Vapor-cell frequency reference for short-wavelength transitions in neutral calcium

TL;DR

This paper explores using a tellurium vapor cell as a frequency reference for calcium atomic transitions at 423nm and 431nm, aiding in optical clock development and laser stabilization.

Contribution

It demonstrates the characterization of Te$_2$ spectrum near calcium transitions and discusses its application for laser frequency stabilization in calcium atomic clocks.

Findings

Te$_2$ vapor cell provides a stable frequency reference near calcium transitions.

Application to calcium beam clock shows potential for reducing Doppler shift instability.

Enhanced detection methods for calcium transitions using Te$_2$ reference.

Abstract

We have characterized the molecular tellurium (Te$_2$) spectrum in the vicinity of the 423nm $^1S_0-^1P_1$ and the 431nm $^3P_1-^3P_0$ transitions in neutral calcium. These transitions are relevant to optical clocks for atomic-beam characterization and cooling (423nm) and enhanced detection (431nm). The use of a Te$_2$ vapor cell as a frequency reference has many advantages over other laser stabilization techniques, and we discuss an application to measuring the instability due to the second-order Doppler shift in a calcium beam clock.