Spectroscopy and frequency measurement of the 87Sr clock transition by laser linewidth transfer using an optical frequency comb

We performed spectroscopic observations of the 698-nm clock transition in Sr-87 confined in an optical lattice using a laser linewidth transfer technique A narrow-linewidth laser interrogating the clock transition was prepared by transferring the linewidth of a master laser (1064 nm) to that of a slave laser (698 nm) with a high-speed controllable fiber-based frequency comb. The Fourier-limited spectrum was then observed for an 80-ms interrogating pulse. We determined that the absolute frequency of the 5s(2) S-1(0)-5s5p P-3(0) clock transition in Sr-87 is 429 228 004 229 872.0 (1.6) Hz referenced to the SI second. (C) 2014 The Japan Society of Applied Physics