Diode-based difference-frequency pulsed laser photo-acoustic system for trace gas sensing

Summary form only given. Many trace gases, particularly volatile organic compounds, have their fundamental absorption lines in the mid-infrared region of the electromagnetic spectrum around 3.3 /spl mu/m. In order to be able to detect these trace gases, e.g. for environmental sensing, broadly tunable narrowband laser sources are needed. The source used in this study is based on difference-frequency generation (DFG). We employ a diode-pumped pulsed Nd:YAG laser as pump beam and a continuous-wave external cavity diode laser tunable between 1550 and 1610 nm as signal beam. An antireflex-coated PPLN is used for DFG. We present to our best knowledge the first photo-acoustic measurements performed with such a system.