Micro-Photoacoustic Cell with Integrated Microphone for Sub-Ppm Gas Sensing

This paper demonstrates, for the first time, an on-chip integration of a photoacoustic (PA) detector, one of the main building blocks required for chemical sensing. This MEMS PA detector consists of a miniaturized PA cell within an acoustic transducer based on an innovative microphone architecture. Coupled with a quantum cascade laser (QCL) source, this trace gas detector can measure very low concentrations of less than one part per million.