  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.
