Accession Number:

ADA370924

Title:

Diode-Pumped Nd:YAG/Cr(4+):YAG MicroChip-Laser System at 214.8 nm for the Detection of NO

Descriptive Note:

Final rept. 1 Nov 96-30 Apr 99

Corporate Author:

AERODYNE RESEARCH INC BILLERICA MA

Personal Author(s):

• Wormhoudt, J.
• Shorter, J. H.
• Zayhowski, J.J.
• Cook, C.

Report Date:

1999-07-30

Pagination or Media Count:

24.0

Abstract:

A passively Q-switched 214.8-nm NdYAGCr4YAG microchip-laser system for the detection of NO was designed, constructed, and tested. The system uses the fifth harmonic of the 1.074-micrometers transition in NdYAG to detect NO at the few-parts-per-billion level. A significant challenge was the development of an environmentally stable coating to provide the necessary discrimination between the 1.074-micrometers laser line and the stronger transition at 1.064 micrometers. The exact position of the fifth-harmonic frequency was determined using NO fluorescence excitation spectra to be 46556cm. We observed a detection sensitivity for NO of about 15 ppbv in a simple, compact optical system. Earlier observations of SO2 imply a similar or better sensitivity for the current system, while green-light excitation of NO2 fluorescence yielded a detection limit of order 1 ppmv. Applications of the laser system described here include explosives sensors based on detection of NO from thermal decomposition, and NOxSOx monitors for trucks, aircraft and stationary sources.

Descriptors:

• *NITROGEN OXIDES
• *DIODE LASERS
• LASER PUMPING
• Q SWITCHING
• YAG LASERS
• OPTICAL EQUIPMENT
• STABILITY
• DETECTION
• FLUORESCENCE
• AIRCRAFT
• EXCITATION
• CHIPS(ELECTRONICS)
• EXPLOSIVES
• COATINGS
• SPECTRA
• CHROMIUM
• MONITORS
• PYROLYSIS
• NEODYMIUM LASERS

Subject Categories:

• Lasers and Masers

Distribution Statement:

APPROVED FOR PUBLIC RELEASE