Whispering Gallery Mode Stabilization of Quantum Cascade Lasers for Infrared Sensing and Spectroscopy

Narrow-linewidth lasers are key elements in optical metrology and spectroscopy. From their spectral purity, the measurements accuracy and the overall quality of collected data critically depend. Crystalline microresonators have undergone an impressive development in the last decade, opening new ways to photonics from the mm to the mu m scale. Their wide transparency range and high Q-factor make them suitable for integration in compact apparatuses for precision spectroscopy from the visible to the mid-IR. Here, we present our recent results on frequency stabilization and linewidth narrowing of quantum cascade lasers using crystalline Whispering Gallery Mode Resonators for mid-IR precision spectroscopy.