A narrowband infrared source based on orientation-patterned GaAs for standoff detection of chemicals

International audienceThis paper presents our work on a pulsed single-frequency tunable optical parametric oscillator based on orientation-patterned gallium arsenide. Owing to crystal temperature tuning, this source covers the 10.2–11.2 and 7.6–8.6 μm ranges in single-longitudinal mode operation with a linewidth below 30 MHz. Standoff detection of ammonia around 10.35 and 10.5 μm is performed by implementing this source in an Integrated Path Differential Absorption Lidar (IP-DIAL) setup

Multispecies high-energy emitter for CO₂, CH₄, and H₂O monitoring in the 2 μm range

International audienceWe demonstrate the first emitter, based on a single optical source device, capable of addressing three species of interest (CO2, CH4, and H2O) for differential absorption Lidar remote sensing of atmospheric greenhouse gases from space in the 2 μm region. It is based on an amplified nested cavity optical parametric oscillator. The single frequency source shows a total conversion efficiency of 37% and covers the 2.05–2.3 μm range

Differential absorption lidar for water vapor isotopologues in the 1.98 μm spectral region: sensitivity analysis with respect to regional atmospheric variability

International audienceLaser active remote sensing of tropospheric water vapor is a promising technology to complement passive observational means in order to enhance our understanding of processes governing the global hydrological cycle. In such context, we investigate the potential of monitoring both water vapor H2 16 O and its isotopologue HD 16 O using a differential absorption lidar (DIAL) allowing for ground-based remote measurements at high spatio-temporal resolution (150 m and 10 min) in the lower troposphere. This paper presents a sensitivity analysis and an error budget for a DIAL system under development which will operate in the two-micrometer spectral region. Using a performance simulator, the sensitivity of the DIAL-retrieved mixing ratios to instrument-specific and environmental parameters is investigated. This numerical study uses different atmospheric conditions ranging from tropical to polar latitudes with realistic aerosol loads. Our simulations show that the measurement of the main isotopologue H2 16 O is possible over the first 1.5 km of atmosphere with a relative precision in the water vapor mixing ratio of <1% in a mid-latitude or tropical environment. For the measurement of HD 16 O mixing ratios under the same conditions, relative precision is shown to be of similar order, thus allowing for the retrieval of rangeresolved isotopic ratios. We also show that expected precisions vary by an order of magnitude between tropical and polar conditions, the latter giving rise to reduced precision due to low water vapor content and low aerosol load. Such values have been obtained for a commercial InGaAs PIN photodiode, as well as temporal and line-of-sight resolutions of 10 min and 150 m, respectively. Additionally, using vertical isotopologue profiles derived from a previous field campaign, precision estimates for the HD 16 O isotopic abundance are provided