# Third-harmonic-generation of a diode laser for quantum control of beryllium ions

## TL;DR

This paper demonstrates a novel all-semiconductor system generating 313 nm ultraviolet light via third-harmonic generation, enabling advanced quantum control of beryllium ions for quantum information applications.

## Contribution

It introduces a new diode laser-based method for efficient third-harmonic generation at 313 nm for quantum control of beryllium ions.

## Key findings

- Generated 36 mW of coherent UV radiation at 313 nm.
- Enabled laser cooling and sympathetic cooling of beryllium ions.
- Demonstrated a compact, all-semiconductor system for quantum control.

## Abstract

We generate coherent ultraviolet radiation at 313 nm as the third harmonic of an external-cavity diode laser. We use this radiation for laser cooling of trapped beryllium atomic ions and sympathetic cooling of co-trapped beryllium-hydride molecular ions. An LBO crystal in an enhancement cavity generates the second harmonic, and a BBO crystal in a doubly resonant enhancement cavity mixes this second harmonic with the fundamental to produce the third harmonic. Each enhancement cavity is preceded by a tapered amplifier to increase the fundamental light. The 36-mW output power of this all-semiconductor-gain system will enable quantum control of the beryllium ions' motion.