nanoplus Nanosystems and Technologies GmbH | Date: 2015-05-01
Embodiments relate to a semiconductor laser having a multilayer structure including a ridge and two material removal areas adjacent to the ridge on either side, the multilayer structure being arranged on a substrate and a layer expansion plane being defined by a surface of the substrate, the ridge having at least one active region and at least the active region being spatially limited by passages between the ridge and the material removal areas in one dimension of the layer expansion plane, the active region having a layer structure for forming an interband cascade laser.
nanoplus Nanosystems and Technologies GmbH | Date: 2014-10-24
Yacovitch T.I.,Aerodyne Research, Inc. |
Herndon S.C.,Aerodyne Research, Inc. |
Roscioli J.R.,Aerodyne Research, Inc. |
Floerchinger C.,Aerodyne Research, Inc. |
And 20 more authors.
Environmental Science and Technology | Year: 2014
Methane is an important greenhouse gas and tropospheric ozone precursor. Simultaneous observation of ethane with methane can help identify specific methane source types. Aerodyne Ethane-Mini spectrometers, employing recently available mid-infrared distributed feedback tunable diode lasers (DFB-TDL), provide 1 s ethane measurements with sub-ppb precision. In this work, an Ethane-Mini spectrometer has been integrated into two mobile sampling platforms, a ground vehicle and a small airplane, and used to measure ethane/methane enhancement ratios downwind of methane sources. Methane emissions with precisely known sources are shown to have ethane/methane enhancement ratios that differ greatly depending on the source type. Large differences between biogenic and thermogenic sources are observed. Variation within thermogenic sources are detected and tabulated. Methane emitters are classified by their expected ethane content. Categories include the following: biogenic (<0.2%), dry gas (1-6%), wet gas (>6%), pipeline grade natural gas (<15%), and processed natural gas liquids (>30%). Regional scale observations in the Dallas/Fort Worth area of Texas show two distinct ethane/methane enhancement ratios bridged by a transitional region. These results demonstrate the usefulness of continuous and fast ethane measurements in experimental studies of methane emissions, particularly in the oil and natural gas sector. © 2014 American Chemical Society. Source
Wolff M.,Hamburg University of Applied Sciences |
Rhein S.,Hamburg University of Applied Sciences |
Bruhns H.,Hamburg University of Applied Sciences |
Nahle L.,Nanoplus Nanosystems and Technologies GmbH |
And 2 more authors.
Sensors and Actuators, B: Chemical | Year: 2013
To the best of our knowledge, we present for the first time spectroscopic methane measurements using a laser diode at 3.3 μm operated in continuous mode at room temperature. The DFB-type laser emits a maximum optical output power of 1.5 mW with a spectral linewidth below 10 MHz. This novel kind of semiconductor laser allows precise photoacoustic measurements of characteristic methane absorption structures in the v3 band. In addition, the setup enables a detection limit below 1 ppm. © 2013 Elsevier B.V. All rights reserved. Source
Wu T.,University of the Littoral Opal Coast |
Wu T.,CAS Anhui Institute of Optics and Fine Mechanics |
Chen W.,University of the Littoral Opal Coast |
Kerstel E.,University of Groningen |
And 5 more authors.
Optics Letters | Year: 2010
Kalman adaptive filtering was applied for the first time, to our knowledge, to the real-time simultaneous determination of water isotopic ratios using laser absorption spectroscopy at 2.73 μm. Measurements of the oxygen and hydrogen isotopologue ratios δ 18O, δ 17O, and δ 2H in water showed a l-σ precision of 0.72%o for δ 18O, 0.48%o for δ5 17O, and 0.84%o for «5 2H, while sampling the output of the tuned Kaiman filter at 1 s time intervals. Using a standard running average technique, averaging over ∼30 s is required to obtain the same level of precision. © 2010 Optical Society of America. Source