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Title: Semiconductor laser source for natural gas leak detection. Final report, September 1, 1984-March 31, 1985

Technical Report ·
OSTI ID:6316643

The feasibility of using semiconductor lasers as infrared sources for handheld natural gas leak detectors was assessed. The detection system was assumed to be based on the differential absorption (DIAL) technique and to operate at ambient temperatures. The absorption spectra of the major components of natural gas, methane and ethane, were measured in the spectral range from 1.2 to 2.0 micrometers where cryogenic cooling of detectors is not required. Both spectra exhibited absorption features due to overtones of the fundamental C-H stretching modes strong enough to be suitable for DIAL measurements. The literature on semiconductor lasers was reviewed both to determine which types emit in spectral regions overlapping the absorption bands of methane and ethane and which allow the high power pulsed operation necessary for DIAL systems. Lasers made from InGaAs emitting near 1.65 micrometers are suitable for methane detection. However, considerable materials development would be needed to develop a laser for ethane detection. Cleaved-coupled-cavity (CT) laser structures appear to be the most promising means of tuning and narrowing the linewidth of the emitted light. An experiment with a ten-emitter phased array (CT) laser showed significant line narrowing.

Research Organization:
Oregon Graduate Center, Beaverton (USA)
OSTI ID:
6316643
Report Number(s):
PB-86-102811/XAB
Country of Publication:
United States
Language:
English