Physics Graduate Student Symposium (PGSS) | Miniaturized Frequency Combs Enable Advanced Spectroscopies to Leave the Lab and (Maybe) Enter Orbit

Frequency Combs, or pulsed lasers which are capable of emitting many narrow and closely spaced spectral lines (teeth) with fixed phase relationships between adjacent teeth, are an essential tool in precision metrology and spectroscopy. Their usefulness comes from the fact that their entire spectrum can be controlled by just adjusting the time between pulses and the pulse-to-pulse phase slip of their electric field. This means that, using relatively simple control schemes, frequency combs enable the most precise measurements of time and frequency possible, among a plethora of other applications. Typically, however, these light sources are roughly the size of a kitchen table and require the high stability of a lab environment to maintain the controllability of their output. Miniaturized combs exist, in the form of microscopic ring resonators, but these light sources are not very tunable, typically require large and powerful pump lasers to operate, and are expensive to manufacture. These drawbacks are all showstoppers when it comes to allowing frequency comb enabled precision measurement and spectroscopy to leave the lab. We have demonstrated a new, extremely cheap, simple, and low power laser diode-based frequency comb which is roughly the size of a grain of rice. This laser can be battery powered, and its spectrum is highly controllable, making it an ideal light source to allow advanced precision measurement and spectroscopy to leave the lab. In my talk, I will give a brief overview of frequency comb-based measurements, demonstrate the stability and tunability of our new sources, and outline their prospect for future ground- and space-based applications.