Picture of the Day

On-chip, electronically tunable frequency comb

Lasers play a vital role in everything from modern communications and connectivity to biomedicine and manufacturing. Many applications, however, require lasers that can emit multiple frequencies -- colors of light -- simultaneously, each precisely separated like the tooth on a comb. Optical frequency combs are used for environmental monitoring to detect the presence of molecules, such as toxins and in astronomy for searching for exoplanets. However, they have remained bulky and expensive, which limited their applications. So, researchers have started to explore how to miniaturize these sources of light and integrate them onto a chip to address a wider range of applications, including telecommunications, microwave synthesis and optical ranging. But, so far, on-chip frequency combs have struggled with efficiency, stability and controllability. Now, National Science Foundation-funded researchers have developed an integrated, on-chip frequency comb that is efficient, stable and highly controllable with microwaves.

Visit Website | Image credit: Second Bay Studios/Harvard SEAS