• Spectral Energies, 2010-2012, High-Bandwidth Noninvasive Sensor Systems for Measuring Enthalpy and Mass Flux in Detonation-Powered Devices

• 7,889,769 - Multi-spectral laser source employing periodically poled crystal mixer, granted Feb 2011.
• 7,826,061 - High-speed spectrographic sensor for internal combustion engines, granted Nov 2010.
• 7,633,977 - Multispectral laser with improved time division multiplexing, granted Dec 2009.
• 7,619,742 - High-speed spectrographic sensor for internal combustion engines, granted Nov 2009.
• 7,613,214 - Multi-wavelength mode locked laser, granted Nov 2009.

• "Determining the optimum wavelength pairs to use for molecular absorption thermometry based on the continuous-spectral lower-state energy"

An XL, Caswell AW, Lipor JJ, et al., Journal of Quantitative Spectroscopy & Radiative Transfer 112(14): 2355-2362 Sep 2011. A novel technique for selecting wavelengths that optimize the temperature precision of absorption-based thermometry is developed.

• "Quantifying the temperature sensitivity of practical spectra using a new spectroscopic quantity: Frequency-dependent lower-state energy"

An XL, Caswell AW, Sanders ST, Journal of Quantitative Spectroscopy & Radiative Transfer 112 (5): 779-785 Mar 2011.  Individual molecular spectroscopic transition can be characterized by a single, fixed parameter that describes the transition's temperature sensitivity. This lower-state energy is easily computed from measured or simulated spectra and is valuable for detailed assessment of the temperature sensitivity of practical spectra.

• "Validation of Temperature Imaging by H₂O Absorption Apectroscopy using Hyperspectral Tomography in Controlled Experiments"

An X, Kraetschmer T, Takami K, Appl Opt. 50 (4): A29-37 Feb 2011. This paper describes a preliminary demonstration and validation of temperature imaging using hyperspectral H₂O absorption tomography in controlled experiments. PubMed/NLM.

• "Application of time-division-multiplexed lasers for measurements of gas temperature and CH4 and H2O concentrations at 30 kHz in a high-pressure combustor"

Caswell AW, Kraetschmer T, Rein K, et al., Applied Optics 49 (26): 4963-4972 Sep 2010.  Two time-division-multiplexed (TDM) sources based on fiber Bragg gratings were applied to monitor gas temperature, H2O mole fraction, and CH4 mole fraction using line-of-sight absorption spectroscopy in a practical high-pressure gas turbine combustor test article.

• Chevron Energy & Technology Co. Richmond, CA
• Spectral Energies Dayton, OH

• Engine Research Center