A system is described for the absolute frequency measurement of a laser source at 445 THz probing a narrow resonance of a trapped single ion of strontium. The 474-THz frequency from a laser referenced to an iodine-stabilized helium–neon laser and a known 29-THz frequency from a saturation-stabilized carbon dioxide laser are mixed in an AgGaS2 nonlinear crystal to synthesize the 445–THz radiation. A preliminary measurement of the 88Sr+ 5s2S1/2 −4d2D5/2 center frequency yielded a frequency of 444 779 044.14 ± 0.39 MHz (1σ).
© 1996 Optical Society of America
Original Manuscript: November 27, 1995
Published: June 1, 1996
A. A. Madej and K. J. Siemsen, "Absolute heterodyne frequency measurement of the 88Sr+ 455-THz S–D single ion transition," Opt. Lett. 21, 824-826 (1996)