Transportable mid-infrared laser heterodyne radiometer operating in the shot-noise dominated regime.

A transportable laser heterodyne radiometer (LHR) based on an external cavity quantum cascade laser, operating in the mid-infrared (mid-IR) around 8 µm, was developed for ground-based remote sensing of multiple greenhouse gases. A newly available novel flexible mid-IR polycrystalline fiber was first exploited to couple solar radiation, real-time captured using a portable sun-tracker, to the LHR receiver. Compared to free space coupling of sunlight, the technique usually used nowadays in the mid-IR, such fiber coupling configuration makes the LHR system readily more stable, simpler, and robust.

Spectroscopic Measurements of Methane Solid-Gas Equilibrium Clapeyron Curve between 40 and 77 K.

The infrared gas-phase absorption spectrum of methane was used to determine its Clapeyron solid-gas equilibrium curve in the 40-77 K temperature range. For comparative purposes and to obtain more reliable results, two different optical experimental setups were used. At higher temperatures (53-77 K), a single pass cryogenically cooled cell was coupled to a standard low-resolution Fourier transform infrared spectrometer.

UV photodesorption of interstellar CO ice analogues: from subsurface excitation to surface desorption.

Carbon monoxide is after H(2) the most abundant molecule identified in the interstellar medium (ISM), and is used as a major tracer for the gas phase physical conditions. Accreted at the surface of water-rich icy grains, CO is considered to be the starting point of a complex organic--presumably prebiotic--chemistry. Non-thermal desorption processes, and especially photodesorption by UV photons, are seen as the main cause that drives the gas-to-ice CO balance in the colder parts of the ISM.

Balloonborne calibrated spectroradiometer for atmospheric nadir sounding.

Laboratoire de Physique Moléculaire et Applications (LPMA)/Infrared Atmospheric Sounding interferometer (IASI) balloon is a calibrated infrared Fourier transform spectrometer that is used to measure the Earth's atmospheric emission (650-3000 cm(-1)). Operating under a stratospheric balloon, this spectroradiometer provides radiometrically calibrated spectra with an apodized spectral resolution of 0.1 cm(-1), which can be used to retrieve the concentration of atmospheric trace gases such as H2O, CO2, CO, O3, N2O, and CH4.