Quantum cascade laser linewidth investigations for high resolution photoacoustic spectroscopy

• DOI: 10.1364/ao.48.000b80
• Publication Date: 2008-12-05T18:26:38Z
• Authors: Markus Germer; Marcus Wolff
• Keywords: Laser linewidth; Quantum cascade laser; Photoacoustic Spectroscopy; Modulation (music)

High detection selectivity is extremely important for gas analyzers in order to correctly identify the measured compound. Therefore, laser-based systems require a high optical resolution, which primarily depends on spectral linewidth of radiation source. This study examines effective (chirp) pulsed distributed feedback (DFB) quantum cascade laser (QCL) photoacoustic (PA) system. The influence QCL operating parameters pulse duration and current as well impact modulation technique are investigated. Effective linewidths gate modulation, frequency chopper compared. investigations performed by measuring PA spectra nitrogen monoxide absorption lines. results prove strong current. They also demonstrate that has considerable and, consequently, affects analyzer. aim this research determine optimum operational resolution spectroscopy.