Frequency doubling and stabilization of a Tm,Ho:YLF laser at 2051 nm to a high finesse optical cavity

TL;DR

This paper demonstrates the frequency doubling and stabilization of a Tm,Ho:YLF laser at 2051 nm using a high finesse cavity and PDH locking, achieving sub-kHz linewidths suitable for precision ion experiments.

Contribution

It introduces a stabilized 2051 nm laser system with high finesse cavity locking and demonstrates its application in barium ion spectroscopy.

Findings

Laser linewidth less than 500 Hz

Achieved laser-ion coherence times of 2 ms

Intensity noise suitable for quantum experiments

Abstract

Light from a Tm,Ho:YLF laser operating at 2051 nm is frequency doubled then coupled into a high Fabry-Perot cavity with manufacturer quoted finesse in excess of 300,000. The frequency of the laser is stabilized using the Pound-Drever-Hall (PDH) method. A two channel feedback circuit allows for laser frequency stabilization with a bandwidth of 2 MHz. This laser system has been used to drive the 6S1/2 to 5D3/2 transition in 138Ba+, where a 2 ms laser-ion coherence times has been observed, demonstrating a linewidth of less than 500 Hz. The intensity noise of this system is analyzed and found to be acceptable for several proposed experiments on a single trapped barium ion.