Octave Spanning Tunable Frequency Comb from a Microresonator
© 2011 EPFL
A tunable frequency comb with frequencies spanning beyond the first harmonic (from 990 to 2170 nm) has been demonstrated for the first time in a continuous wave laser pumped microresonator.
More than a decade ago, the frequency comb technique was developed at the Max Planck Institute of Quantum Optics by Professor Theodor W. Hänsch.
The new tool has stimulated fundamental research as well as laser development and its applications because it gave rise to a huge increase in the accuracy of measuring optical frequencies.
Already a couple of years ago, the team Prof. Tobias Kippenberg, formerly Leader of the Max Planck Research Group “Laboratory of Photonics and Quantum Measurements” at MPQ, succeeded for the first time in generating optical frequency combs using chip-based microresonators with diameters on the micrometer scale. Now the scientists have made a big step further: their new microresonators produce light over a range of more than an octave and are at the same time precisely tunable (PRL 107, 063901, 1 August 2011).
This achievement brings a variety of applications into reach, such as optical telecommunications or the precise calibration of spectrographs in astrophysics.
