Recent advances and applications of off‐axis integrated cavity output spectroscopy

Abstract

Abstract The off‐axis integrated cavity output spectroscopy (OA‐ICOS) represents a suitable solution in many applications with a simple structure and high sensitivity. The off‐axis configuration allows the continuous spectrum output without cavity mode structure when a continuous wave laser is used while preserving the optical resonator's ability to enhance the optical path by tens of thousands of times. This review summarizes the recent advances and applications of OA‐ICOS in recent decades. The evolutionary process and basic principle of OA‐ICOS are introduced. Various approaches for improving the technical performance and enabling simultaneous multigas measurement are reported. Finally, the various field applications of OA‐ICOS technology and the potential development directions are discussed.