Compact photoacoustic module for methane detection incorporating interband cascade light emitting device

A photoacoustic module (PAM) for methane detection was developed by combining a novel 3.2 mu m interband cascade light emitting device (ICLED) with a compact differential photoacoustic cell. The ICLED with a 22-stage interband cascade active core emitted a collimated power of similar to 700 mu W. A concave Al-coat reflector was positioned adjacent to the photoacoustic cell to enhance the gas absorption length. Assembly of the ICLED and reflector with the photoacoustic cell resulted in a robust and portable PAM without any moving parts. The PAM performance was evaluated in terms of operating pressure, sensitivity and linearity. A 1 sigma detection limit of 3.6 ppmv was achieved with a 1-s integration time. (C) 2017 Optical Society of America