Integrated photonic correlation spectroscopy for faint exoplanet biosignature detection

Exoplanetary biosignatures, molecular compounds which indicate a likelihood of extraterrestrial life, can be detected by highly sensitive spectroscopy of starlight which passes through the atmospheres of exoplanets towards the Earth. Such sensitive measurements can only be accomplished with the next generation of telescopes, leading to a corresponding increase in cost and complexity spectrometers. Integrated astrophotonic instruments are well-suited to address these challenges through their low-cost fabrication and compact geometries. We propose and characterize an integrated photonic gas sensor which detects the correlation between the near-infrared quasi-periodic vibronic absorption line spectrum of a gas and a silicon waveguide ring resonator transmittance comb. This technique enables lock-in amplification detection for real-time detection of faint biosignatures for reduced observation timescales and rapid exoplanetary atmosphere surveys using highly compact instrumentation.