Versatile, high-power 460 nm laser system for Rydberg excitation of ultracold potassium

• Published in: Optics express Vol. 25; no. 13; pp. 14829 - 14839
• Main Authors: Arias, Alda, Helmrich, Stephan, Schweiger, Christoph, Ardizzone, Lynton, Lochead, Graham, Whitlock, Shannon
• Format: Journal Article
• Language: English
• Published: United States 26.06.2017
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.25.014829

We present a versatile laser system which provides more than 1.5 W of narrowband light, tunable in the range from 455-463 nm. It consists of a commercial titanium-sapphire laser which is frequency doubled using resonant cavity second harmonic generation and stabilized to an external reference cavity. We demonstrate a wide wavelength tuning range combined with a narrow linewidth and low intensity noise. This laser system is ideally suited for atomic physics experiments such as two-photon excitation of Rydberg states of potassium atoms with principal quantum numbers n > 18. To demonstrate this we perform two-photon spectroscopy on ultracold potassium gases in which we observe an electromagnetically induced transparency resonance corresponding to the 35s state and verify the long-term stability of the laser system. Additionally, by performing spectroscopy in a magneto-optical trap we observe strong loss features corresponding to the excitation of s, p, d and higher-l states accessible due to a small electric field.