Carrier-envelope phase detection by Quantum Interference Control of Injected Currents
Original Publication Date: 2001-Oct-10
Included in the Prior Art Database: 2005-Jun-09
National Institute of Standards and Technology
Recently there has been a dramatic breakthrough in the field of optical frequency metrology and optical clocks [1-3]. This has been based on the utilization of modelocked lasers, which produce ultrashort (- 10 fs) pulses, to produce a regularly spaced "comb" of optical frequencies. If this comb is sufficiently broad, so that is spans a factor of two in optical frequencies (an octave), it is possible to directly determine the optical frequencies of all of the comb lines by measuring two radio frequencies. These two frequencies are the repetition rate of the modelocked laser (f p) and the carrier-envelope frequency (8). Since these frequencies can be readily compared to a Cs clock, this enables determination of the absolute optical frequencies. This only requires a single modelocked laser, as opposed to the complex chain that was needed prior to this development. We call this a "self-referencing" technique.