The development and characteristics of compact diode laser pumped mid-infrared difference frequency gas sensors are reported. One such tunable cw sensor operates in the 3.3 to 4.4 μm spectral region and uses a diode-seeded fiber amplifier. Results show that fiber coupled sensors are capable of real-time, highly selective and sensitive measurements of numerous trace gas species in ambient air, presently CH4, H2CO, HCl, CO2, N2O, and H2O

© 2000 Optical Society of America

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