Thermal grating effects in infrared degenerate four-wave mixing fro trace gas detection

✍ Scribed by A. Dreizler; T. Dreier; J. Wolfrum

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 591 KB
• Volume: 233
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(94)01486-f

✦ Synopsis

Degenerate four-wave mixing (DFWM) in the infrared region using a single mode CO 2 laser has been used for the detection of ethylene, sulfur hexafluoride and mixtures of these gases with nitrogen and argon in the pressure range up to one atmosphere. The investigations showed that for the low pressure regime ( < 6.5 × 10 3 Pa) the formation of the DFWM signal was dominated by population gratings whereas for high pressures (> 25 × 10 3 Pa) mostly contributions from thermal gratings gave rise to the observed DFWM signal. This behaviour is reproduced by a simple model prediction for these relaxation processes.