Abstract: An energy content meter can spectroscopically quantify oxidation products after oxidation of a combustible mixture. The measured oxidation product concentrations or mole fractions can be converted to an energy content of the un-oxidized combustible mixture using a conversion factor that relates oxygen consumption during oxidation of the combustible mixture to the energy content of the combustible mixture.

Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: A system includes a light source, a detector, at least one pressure sensor, and a control unit. The light source emits light at a wavelength substantially corresponding to an absorption line of a target gas. The detector is positioned to detect the intensity of light emitted from the light source that has passed through the target gas. The pressure sensor detects the pressure of the target gas. The control circuit is coupled to the detector and the light source to adjust the modulation amplitude of the light source based on the pressure detected by the at least one pressure sensor. Related systems, apparatus, methods, and/or articles are also described.

Abstract: Concentrations of a target analyte in a gas mixture containing one or more background analytes having potentially interfering spectral absorption features can be calculated by compensating for background analyte absorption at a target wavelength used to quantify the target analyte. Absorption can be measured at a reference wavelength chosen to quantify the concentration of the background analyte. Using a background gas adjustment factor or function, the absorption measured at the reference wavelength can be used to calculate absorption due to the background analyte at the target wavelength and thereby compensate for this background absorption to more accurately calculate the target analyte concentration in real or near real time. Additional background analytes can optionally be compensated for by using one or more additional reference wavelengths.

Abstract: A laser diode array has a semiconductor layered structure that includes at least one active layer. A heat sink is coupled to semiconductor layered structure. A plurality of laser emitters are formed in the active layer. A majority of the plurality of laser emitters have a spacing between adjacent laser emitters that provides for a more uniform heat distribution.

Abstract: Disclosed is a laser system including a high reflector and an output coupler defining a resonator; a gain medium positioned in the resonator that produces optical gain at more than two desired wavelengths; a coarse selection system, positioned in the resonator and coupled to the gain medium, that produces single transverse modes at the desired wavelengths, with transmission values at the desired wavelengths selected such that power output at the desired wavelengths is maximized, and with transmission values at undesired wavelengths selected to retard lasing at the undesired wavelengths; and a fine selector positioned in the resonator and coupled to the gain medium, having a optical length such that all of the desired wavelengths are substantially simultaneously resonant within the optical length; whereby an output beam is generated. Also disclosed are full-color holography systems and three-dimension laser Doppler velocimetry systems incorporating the inventive laser system.