Development of a 16 μm differential absorption lidar with a quasi-phase-matching optical parametric oscillator and photon-counting detector for the vertical CO_2 profile

Abstract

We have developed a 1.6 microm carbon dioxide (CO(2)) differential absorption lidar utilizing a quasi-phase-matching optical parametric oscillator (OPO) and a photon-counting detector. The operating wavelengths were chosen based on their low interference from water vapor and low temperature sensitivity. The online wavelength was in the (30012<--0001) band of CO(2), which was insensitive to atmospheric temperature. The established OPO laser achieved a 10 mJ, 200 Hz repetition rate at the online and offline wavelengths. Our observations confirmed the statistical error of 2% with 5 h of accumulation for the CO(2) density profile less than 5.2 km. Also, the statistical error of 1% at an altitude of 2 km was demonstrated. The results of the vertical CO(2) concentrations acquired using a 1.6 microm wavelength are presented.

Upconversion-based lidar measurements of atmospheric CO_2

“…The IPDA technique has proven viable for airborne measurements of integrated path concentrations [3], but a pulsed DIAL system is required to get vertical concentration profiles. This has been demonstrated earlier at 1.6 µm with a near infrared PMT and 5 hours of integration time [4], but much shorter integration times are needed for airborne measurements. The limiting factor to obtain this is the noise properties of the receiver system.…”

“…When all the above is taken into consideration, it is expected that the SNR of the optimized upconversion system could show an improvement of two orders of magnitude. The improved QE may allow for range resolved concentration measurements of atmospheric CO 2 , with much shorter integration times than demonstrated in [4]. In a future integrated implementation of the upconversion system, the beam scaling optics will be configured to match the nonlinear process.…”

“…This concerns, in particular, the understanding of the processes that control how the most important anthropogenic greenhouse gases, CO 2 and CH 4 , flow between the various reservoirs [1].…”

2-μm Coherent DIAL for CO2, H2O and Wind Field Profiling in the Lower Atmosphere: Instrumentation and Results

“…Typical natural variation due to its diurnal cycle (uptake by the vegetation, rectifier effect) are around 5% close to the surface but decrease to 0.1% for turbulent fluctuations in the convective boundary layer. Although differential absorption lidar experiments emerged in the last decade [1][2][3] the technology faced two main limitations to reach such precision: (i) a powerful and high PRF dual wavelength single mode emitter for coherent DIAL system and (ii) an efficient photodetector (i.e. avalanche photodiodes) in the near infrared for direct detection DIAL.…”

Development of optical parametric amplifier for lidar measurements of trace gases on Earth and Mars

“…While our primary target is CH 4 on Earth and Mars, the OP A approach will allow a new capability for general planetary Iidar instruments. While many gas sensing Iidar systems are based on optical parametric oscillator (OPO) approach [3][4][5][6][7], our OPA approach is simpler, especially when narrow-lincwidth. high-power pump and seed lasers are available.…”