Photoacoustic spectroscopy is a useful monitoring technique that is well suited for trace gas detection
applications. A sensitive and compact differential photoacoustic method for trace gas measurements is proposed. The
technique possesses favorable detection characteristics that suggest the system dimensions may scale to a micro-system
design. The objective of present work is to incorporate two strengths of the Army Research Laboratory (ARL);
Interband Quantum Cascade Laser (ICL) source development and Chemical and Biological Sensing; we then applied
them into a monolithic micro-electromechanical systems (MEMS) photoacoustic trace gas sensor. Previous data has
shown that reducing the size of the photoacoustic cell can produce a very sensitive sensor using a CO2 laser. Recent
work has shown that with further reduction in the size of the photoacoustic cell in combination with an ICL as the
source, produces favorable detection limits for Dimethyl Methyl Phosphonate (DMMP) a precursor to a nerve agent.
These studies involve the incorporation of an ICL source operating at ~3.45 &mgr;m. This experimentation is expected to
culminate in the creation of an extremely versatile MEMS photoacoustic sensor.
Photoacoustic spectroscopy is a useful monitoring technique that is well suited for trace gas detection. The
technique also possesses favorable detection characteristics when the system dimensions are scaled to a
micro-system design. The objective of present work is to incorporate two strengths of the Army Research
Laboratory (ARL), Quantum Cascade Laser (QCL) source development and chemical and biological
sensing into a monolithic micro-electromechanical systems (MEMS) photoacoutic trace gas sensor.
Past examination of a one quarter scale photoacoustic (PA) macro-cell has indicated a pathway to incorporate a
photoacoustic resonance structure in a micro-mechanical platform. Initial studies involve the incorporation
of a QCL source operating @ ~3.45 μm into the PA macro-cell system as a means to discern proper
operational characteristics in relation to the photoacoustic cell design. Results will be presented describing
beam conditioning, modulation control and wavelength selection associated with the QCL source.
Some preliminary information regarding MEMS-scale designs based off of hybrid concept, involving
commercially available microphone and fully fabricated MEMS photoacoustic resonator will be described.
Conference Committee Involvement (3)
Smart Biomedical and Physiological Sensor Technologies VII
8 April 2010 | Orlando, Florida, United States
Smart Biomedical and Physiological Sensor Technology VI
16 April 2009 | Orlando, Florida, United States
Smart Biomedical and Physiological Sensor Technology V