Watt-level blue light for precision spectroscopy, laser cooling and trapping of strontium and cadmium atoms

TL;DR

This paper reports the development of high-power, narrow-linewidth blue laser sources at 457.49 nm and 460.86 nm for precision spectroscopy, laser cooling, and trapping of cadmium and strontium atoms, using a novel VECSEL-based frequency doubling approach.

Contribution

It introduces a novel gain chip design enabling Watt-level laser output at 915-928 nm, leading to efficient frequency doubling for deep ultraviolet spectroscopy of cadmium.

Findings

Achieved Watt-level laser power at target wavelengths.

Observed all isotopic transitions of cadmium in a single sweep.

Measured and provided new isotope shift data for cadmium.

Abstract

High-power and narrow-linewidth laser light is a vital tool for atomic physics, being used for example in laser cooling and trapping and precision spectroscopy. Here we produce Watt-level laser radiation at 457.49 nm and 460.86 nm of respective relevance for the cooling transitions of cadmium and strontium atoms. This is achieved via the frequency doubling of a kHz-linewidth vertical-external-cavity surface-emitting laser (VECSEL), which is based on a novel gain chip design enabling lasing at > 2 W in the 915-928 nm region. Following an additional doubling stage, spectroscopy of the $^1S_0\to{}^1P_1$ cadmium transition at 228.89 nm is performed on an atomic beam, with all the transitions from all eight natural isotopes observed in a single continuous sweep of more than 4 GHz in the deep ultraviolet. The absolute value of the transition frequency of Cd-114 and the isotope shifts relative to this transition are determined, with values for some of these shifts provided for the first time