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By utilizing progress in millijoule-level pulsed fiber lasers operating in the 1.96 µm spectral range, we introduce a concept utilizing a spaceborne differential absorption barometric lidar designed to operate within the 1.96 µm CO2 absorption band for remote sensing of Martian atmospheric properties. Our focus is on the online wavelength situated in the trough region of two absorption lines, selected due to its insensitivity to laser frequency variations, thus mitigating the necessity for stringent laser frequency stability. Our investigation revolves around a compact lidar configuration, featuring reduced telescope dimensions and lower laser pulse energies. These adjustments are geared towards minimizing costs for potential forthcoming Mars missions. The core measurement objectives encompass the determination of column CO2 absorption optical depth, columnar CO2 abundance, surface atmospheric pressure, and vertical distributions of dust and cloud layers. Through the amalgamation of surface pressure data with atmospheric temperature insights garnered from sounders and utilizing the barometric formula, the prospect of deducing atmospheric pressure profiles becomes feasible. Simulation studies validate the viability of our approach. Notably, the precision of Martian surface pressure measurements is projected to surpass 1 Pa when the aerial dust optical depth is projected to be under 0.7, a typical airborne dust scenario on Mars, considering a horizontal averaging span of 10 km. [ABSTRACT FROM AUTHOR]

A novel technique that enables coherent detection of spontaneous Brillouin scattering in the radiofrequency ( OCIS codes: 060.2370, 120.0280.

The high detection sensitivity available from intracavity laser spectroscopy (ILS) is extended into the near infrared by solid-state laser systems operating with relatively narrow (~0.002 [micro]m) bandwidths for three [CO.sub.2] absorption features of importance to an understanding of planetary atmospheres. The absolute intensities and pressure-broadening properties of the P(12), P(14), and P(16) lines of the [Sigma]-[Sigma] band (12 [degrees] 1-00 [degrees] 0) of [CO.sub.2] (at 2.0129, 2.0136, and 2.0143 [micro]m) are measured quantitatively by ILS with a Tm:YAG laser operating near 2.0 [micro]m. The temperature dependencies of these absolute intensities and collisional-broadening parameters for these three [CO.sub.2] features are also measured over the 110-300 K range. The 3.0-km equivalent absorption path length available from the ILS Tm:YAG system is used to enhance detection sensitivity by more than a factor of 1.5 x [10.sup.4] while maintaining a physical sample cell path length of ~20 cm. The enhanced detection sensitivity of ILS permits absolute intensities and collisional-broadening parameters to be measured from [is less than] 1-Torr [CO.sub.2] over a series of temperatures, conditions that emulate those found in the atmospheres of Mars, Triton, and Venus. [C] 2001 Optical Society of America OCIS codes: 120.1880, 120.4820, 140.3070, 140.3480, 300.6390, 350.1270.