Absorption sensors

Gupta B.D., Sharma A., Singh C.D., Fiber optic evanescent-wave absorption sensors based on uniform and tapered fibers, Proc. 2nd Europtrode (1994), Firenze, p.189. 

The microresonator therefore can also be used as a sensitive absorption sensor. In both set-ups as refractive or absorption sensor, the ultimate sensitivity is determined by the slope of the resonance peak, which is related to the resonator losses. 

Theoretical Analysis of Microcavity-Enhanced Absorption Sensors... 

Paul, P. H. Kychakoff, G., Fiber optic evanescent field absorption sensor, Appl. Phys. Lett. 1987,51,12 14... 

Furlong, E. R., D. S. Baer, and R. K. Hanson. 1998. Real-time adaptive combustion control using diode-laser absorption sensors. 27th Symposium (International) on Combustion Proceedings. Boulder, CO. 

Apart from the aforementioned most frequently used sensor technologies, also selective electrochemical sensor combinations have been commercialised for use in dedicated applications. The combination of electrochemical CO, H2S, SO2 and NH3 sensors was used for quality and freshness control of foods like fish [98] and meat [99]. Combinations of MOSs and MOSFETs supplemented with a selective IR absorption sensor for carbon dioxide and a humidity sensor for measuring relative humidity were also described [100]. 

Emission measuring sensors also need an internal calibration source. In the case of absorption sensors, the external source most often served as the standard. In the case of emission, a reference source is usually incorporated in the instrument to certify instrument performance and provide an absolute reference. 

Bingham, G.E., Gillespie, C.H., McQuaid, J.H., Lawrence Livermore National Laboratory, and Dooley, D.F., Molectron Corp., A miniature, battery-powered, pyroelectric detector-based differential infrared absorption sensor for ambient concentrations of carbon dioxide, Ferroelectrics, 34, 15-19,... 

Fig. 24. Micro Analysis System, a Structure of NAS with two flow sensors, two pumps and an absorption sensor modul. b Component lay-out of MAS...

Coating-based fibers are the largest class of indirect absorption sensors. In this design, a small section of the optical fiber passive cladding is replaced by an active... 

Goldstein N Spectral Sciences, Burlington, Massachusetts Development of a diode laser absorption sensor for measurement of trace concentrations of ammonia, for potential applications in atmospheric chemistry and pollution monitoring. U.S. DOE... 

Figure 10.1 Schematic of the Stanford PDE facility, with VCSEL-absorption sensor applied to measure gas temperature and pressure near the exit. Detector 1 monitors Cs absorption Uneshapes and detector 2 monitors thermal emission from Cs. Dimensions...

Allen, M. G. "Diode Laser Absorption Sensors for Gas-Dynamic and Combustion Flows." Measurement Science and Technology 9 (1998) 545-62. 

These criteria limit the applicahility of fluorescent dye-based sensors to only a handful of analytes. If a fluorescence-based method does not exist or is Incompatible with an optical sensor, an absorption sensor is the only alternative. There exist a large number of different absorbing dyes that are sensitive, selective and absorb in convenient regions of the spectrum. Several absorbance-based fiber-optic sensors have been described (8,25.26). Unfortunately, a major drawback with absorption spectroscopy is its inherent insensitivity. We decided to explore the possibility of using other optical techniques that can be used with indirect methods. A successful example has been presented which combines the sensitivity of the fluorescence measurement with the specificity of an absorbing dye and is based on an energy transfer mechanism (15). 

Allen MG (1998) Diode laser absorption sensors for gas-dynamic and combustion flows. Meas Sci Technol 9 545-562 Anderson MS, Andringa JM, Carlson RW, Conrad P, Hartford W, Shafer M, Soto A, Tsapin AI, Dybwad JP, Wadsworth W, Hand K (2005) Fourier transform infrared spectroscopy for Mars science. Rev Sci Instrum 76 034101 Ashizawa H, Yamaguchi S, Endo M, Ohara S, Takahashi M, Nanri K, Fujioka T (2003) Development of a nitrogen dioxide gas sensor based on mid-infrared absorption spectroscopy. Rev Laser Eng 31 151-155 Baldini F, Chester AN, Homola J, Martellucci S (eds) (2006) Optical chemical sensors. Springer, Dordrecht Bansal L (2004) Development of a fiber optic chemical sensor for detection of toxic vapors. Ph.D. thesis, Drexel University, Philadelphia, PA... 

Hanna SF, Barron-jimenez R, Anderson TN, Lucht RP, Caton JA, Walther T (2002) Diode-laser-based ultraviolet absorption sensor for nitric oxide. Appl Phys B 75 113-117 Harrington A (2002) Infrared fibers. In Bass M, Van Stryland EW (eds) Fiber optic handbook fiber, devices, and systems for optical communications. Chap 14. McGraw-HiU, New York Haus J (2010) Optical sensors basics and applications. WUey-VCH, Weinheim Hecht J (1992) The laser guidebook, 2nd edn. McGraw-Ffill, New York... 

Magnuson JK, Anderson TN, Lucht RP, Wjayasarathy UA, Oh H, Annamalai K, Caton JA (2008) Application of a diode-laser-based ultraviolet absorption sensor for in situ measurements of atomic mercury in cotil-combustion exhaust. Energy Fuel 22 3029-3036... 

Dazzi, A. et al. (2006) Subwavelength infrared spectromicroscopy using an AFM as a local absorption sensor. Infrared Phys. TechnoL, 49 (1-2), 113-121. 

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