We are proposing Supercontinuum Waveguides for Extreme Radial-Velocity Instrumentation (SWERVI). The SWERVI platform will be an integrated-photonics subsystem for the calibration of current and next-generation astronomical spectrographs with precision-radial velocity (PRV) sensitivity <10 cm/s. The proposed module will use nonlinear nanophotonic waveguides to efficiently and controllably broaden the optical spectrum of an input frequency comb laser, to serve as the broadband calibration source in PRV measurements. Our key innovations will build on our Phase 1 work to include: experimental demonstration of multi-stage coherent broadening in tantala (Ta2O5) photonic circuits, two-channel output to support self-referencing of the frequency comb, and fully packaged modules in a robust enclosure for use in demanding environments. When coupled with a high-repetition-rate comb source, the SWERVI system will enable new PRV calibration sources with spectral coverage virtually anywhere in the visible and near-infrared, while reducing power consumption and complexity through photonic integration. This system addresses a critical technology gap for extreme PRV measurements to detect and study exoplanets. Beyond PRV instrumentation, further development and commercialization of this nonlinear integrated-photonics platform will enable new capabilities in terrestrial and space-borne applications, such as atmospheric spectroscopy, precision timing and navigation, and optical communications.
The development of nonlinear supercontinuum waveguides for broadband optical spectrograph calibration directly addresses the Tier 2 technology gap in the measurement sensitivity of stellar radial velocities for exoplanet detection. Moreover, this technology will have synergies with other important NASA programs through integration with next-generation optical atomic clocks for satellite navigation and timing, as well as space-based spectroscopic monitoring of Earth’s atmosphere to track long-term changes in the planet’s climate.
Supercontinuum generation can be used as a broadband source for photonic device testing, white light interferometry, and several biological imaging modalities. In particular, tantala has very broad transparency and is applicable to mid infrared spectroscopy of trace gases and organic molecules. Microcombs, a closely related technology, are additionally of great interest for optical communications.