VECSEL systems for generation and manipulation of trapped magnesium ions

TL;DR

This paper demonstrates VECSEL-based laser systems capable of generating multiple wavelengths for trapping and manipulating magnesium ions, offering a versatile and scalable alternative to traditional laser sources in quantum information experiments.

Contribution

The authors develop and characterize VECSEL systems with nonlinear frequency conversion for all essential laser tasks in magnesium ion quantum experiments, showcasing their potential as flexible, power-scalable laser sources.

Findings

Generated 570.6 nm light for photoionization of magnesium.

Produced 285.3 nm light for resonant interactions with neutral Mg.

Achieved Doppler cooling and coherent manipulation of Mg+ ions.

Abstract

Experiments in atomic, molecular, and optical (AMO) physics rely on lasers at many different wavelengths and with varying requirements on spectral linewidth, power, and intensity stability. Vertical external-cavity surface-emitting lasers (VECSELs), when combined with nonlinear frequency conversion, can potentially replace many of the laser systems currently in use. Here we present and characterize VECSEL systems that can perform all laser-based tasks for quantum information processing experiments with trapped magnesium ions. For photoionization of neutral magnesium, 570.6$\,$nm light is generated with an intracavity frequency-doubled VECSEL containing a lithium triborate (LBO) crystal for second harmonic generation. External frequency doubling produces 285.3$\,$nm light for resonant interaction with the $^{1}S_{0}\leftrightarrow$ $^{1}P_{1}$ transition of neutral Mg. Using an externally frequency-quadrupled VECSEL, we implement Doppler cooling of $^{25}$Mg$^{+}$ on the 279.6$\,$nm $^{2}S_{1/2}\leftrightarrow$ $^{2}P_{3/2}$ cycling transition, repumping on the 280.4$\,$nm $^{2}S_{1/2}\leftrightarrow$ $^{2}P_{1/2}$ transition, coherent state manipulation, and resolved sideband cooling close to the motional ground state. Our systems serve as prototypes for applications in AMO requiring single-frequency, power-scalable laser sources at multiple wavelengths.