Ultra-precise measurement of optical frequency ratios

We developed a novel technique for frequency measurement and synthesis, based on the operation of a femtosecond comb generator as transfer oscillator. The technique can be used to measure frequency ratios of any optical signals throughout the visible and near-infrared part of the spectrum. Relative uncertainties of $10^{-18}$ for averaging times of 100 s are possible. Using a Nd:YAG laser in combination with a nonlinear crystal we measured the frequency ratio of the second harmonic $\nu_{SH}$ at 532 nm to the fundamental $\nu_0$ at 1064 nm, $\nu_{SH}/\nu_0 = 2.000 000 000 000 000 001 \times (1 \pm 7 \times 10^{-19})$.Comment: 4 pages, 4 figure

Media 2: Endless frequency shifting of optical frequency comb lines

Originally published in Optics Express on 11 March 2013 (oe-21-5-5793

Media 1: Endless frequency shifting of optical frequency comb lines

Originally published in Optics Express on 11 March 2013 (oe-21-5-5793

Introduction to the issue on stabilization of mode-locked lasers

Peer reviewed: YesNRC publication: Ye