Frequency combs can be used to search for other planets Today’s Video of the Day from the National Institute of Standards and Technology (NIST) describes how scientists are using frequency combs to search for other planets.
A frequency comb has teeth that are used to measure the frequency of light, and was originally developed for making measurements of lasers in the laboratory. Spectrum of the light from the two-laser frequency combs installed on the High Accuracy Radial Velocity Planet Searcher. A frequency comb allows a direct link from radio frequency standards to optical frequencies.
The most popular way of generating a frequency comb is with a mode-locked laser. Such lasers produce a series of optical pulses separated in time by the round-trip time of the laser cavity. Applications of Frequency Combs in Metrology and Other Areas As shown above, frequency combs can be used for the measurement of absolute optical frequencies. More precisely, this means that optical frequencies are related to the microwave frequency e.g. from a cesium clock. In other words, a frequency comb can serve as an optical clockwork.
Frequency combs can be used to search for other planets as seen above in video helping researchers measure and track the frequency. Frequency combs can also be used to measure ratios of optical frequencies with extremely high precision, which is not even limited by laser noise . Apart from frequency metrology, other applications are possible in high-precision spectroscopy
Video Credit: NIST