A combined infrared–optical frequency-standard scheme has been demonstrated with a single ion of ytterbium. The optical 2S1/2–2D5/2 reference transition at 411 nm and the infrared 2F7/2–2D5/2 3.43-µm transition were driven sequentially. The structure of the infrared 2F7/2–2D5/2 reference transition at 3.43 µm has also been studied. Infrared transition linewidths of 300 kHz were observed. The output of a Nd:YAG laser and an extended-cavity diode laser were difference-frequency mixed in a crystal of AgGaS2 to produce narrow-linewidth light at 3.43 µm . Both lasers were frequency stabilized to high-finesse reference cavities.
© 1998 Optical Society of America
P. Taylor, M. Roberts, G. P. Barwood, and P. Gill, "Combined optical-infrared single-ion frequency standard," Opt. Lett. 23, 298-300 (1998)