Development of 2.05 m m Fiber Lasers for CO - PowerPoint Presentation

1. Development of 2.05 mm Fiber Lasers for CO2 DIAL Lidar Measuring Martian CO2 and PressureZhaoyan Liu1*, Joel Campbell1, Bing Lin1, Jirong Yu2, and Shibin Jiang31*NASA Langley Research Center, Hampton, VA23681, USA, Zhaoyan.liu@nasa.gov2Science Technology Corporation, Hampton, VA23666, USA3AdValue Photonics Inc, Tucson, USAIntroduction: The Decadal Survey by the National Academy of Sciences in the United States and NASA’s Science Mission Directorate (SMD) Science Plan both require global CO2 observations for the Martian atmospheric pressure, dynamics and chemistry. However, there are significant observational gaps in polar regions and during nighttime for global air pressure and CO2 on Mars. Therefore, recently we proposed a new concept of Martian differential absorption lidar (DIAL) operating in the 2.05 mm CO2 absorption band for global, including poles, atmospheric CO2 and pressure observations day and night [1]. Based on the concept, we are awarded to develop 2.05 mm fiber lasers by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Program. The laser is designed to be an all-fiber master oscillator and power amplifier (MOPA) system with laser output of ~3 mJ at a repetition frequency of 2 kHz.  The primary master oscillator (PMO) is locked to the center (2.0504280 mm) of the selected CO2 absorption line. The frequency of a second MO (SMO) is locked to that of PMO. This SMO frequency is adjustable and switched between the online (2.05044156 mm) and offline (2.05050812 mm) wavelengths. The online wavelength is optimally selected so that the CO2 absorption optical depth (AOD) is ~1.1 at 3 km and the measurement in the low Martian atmosphere has largest signal-to-noise ratio. The online wavelength can also be adjusted to a line slope location where AOD is larger to observe atmospheric pressure at higher altitudes. We will present more detail about this project and instrument development at the conference. Ref DetTelescopeSci DetData ProcessorAtmosphereFiber Optical AmplifierBeam SplitterWavelength LockingControl UnitLaser Sourcel1, l2, …, lnCollimatorTRANSMITTERRECEIVERADCTIALowpass FilterDIAL System500mW2050nm SF Seed10um-core gain fiberAOMAOM20um-core gain fiber20um-core gain fiber~1uJ, ~2mW~20uJ~200uJ>30um-core gain fiber20mW2kHz, 500ns250nJ, 0.5mW~1-3mJ 2kHz, 500ns~2-3μJ, 5mWPulse ShapingPulse GeneratorPower Amplifier ModuleFiber cableFiber cable (Ref, ~5mW)Master Oscillator ModuleDiagram of an all-fiber master oscillator and power amplifier (MOPA) laserLaser to DevelopMarsCALIPSO/EarthFigure of MeritRemarkSatellite altitude (km) 2507108Range2Satellite ground speed (km/s) 3.457.52.1Average over same timeSolar radiation constant (kW/m2)0.591.3612.3Background noiseVisible to IR irradiance ratio~ 220532 nm (CALIPSO) vs 2050 nm (Mars DIAL)Photon number per mJ1.0320e+282.6782e+27~ 3.9Shot noise SNR = N1/2Atmospheric BackscatterDust from surface up to ~50 kmAerosol in the low atmosphereLaser Pulse energy, online/offline (mJ) 5/2Pulse repetition frequency (Hz)1000Wavelengths: primary, secondary, and offline (nm) 2050.44156, 2050.43779, 2050.50812Telescope Diameter (m) 1DetectorDRS APDOther system parametersAdapted from the CALIPSO lidarSatellite altitude (km) 250Satellite ground speed (km/s) 3.45Comparison of space lidar measurements on Mars (CO2 DIAL) and Earth (CALIPSO)Specs used in simulations for the proposed Mars DIAL systemAbsorption Optical Depth, AODWavelength (mm)R(32)2n1+n3CO2 Absorption LinesBackground (a) Extinction Profile(b) Surface Column DAOD Relative Error(c) Nighttime Signal-to-Noise Ratio(d) DAOD Relative Error ProfileSimulation ResultsSummaryWe proposed use of a differential absorption barometric lidar operating at the 2-μm CO2 absorption band to remotely sense Martian global atmospheric CO2 amount and air pressure for both day and night. Simulations, based on the Mars's observed environmental conditions, technically available laser systems, and optimal selection of lidar online and offline wavelengths proposed here, showed that the considered CO2 lidar can enable CO2 and pressure measurements from the surface to the atmosphere up to about a 13-km altitude with relative errors within 1%. This 1% error requirement is comparable to or better than that of passive remote sensing observations. With the strong surface return signals, however, an even more precise surface air pressure measurement within 1 Pa precision at a 5-km horizontal resolution is achievable when the airborne dust optical depth is smaller than 1.5 (or non dust storm cases). This would provide important data for Mars's dynamic and climate studies and obtain CO2 seasonal dynamic information for Martian weather and climate systems. Recently we are awarded to develop 2.05 mm fiber lasers by the NASA PICASSO Program. The laser is designed to be an all-fiber MOPA system with laser output of ~3 mJ at a repetition frequency of 2 kHz.  References: [1] Lin, B., & Liu, Z. (2021), Martian atmospheric CO2 and pressure profiling with differential absorption lidar: System consideration and simulation results, Earth and Space Science, 8, e2020EA001600. https://doi.org/10.1029/2020EA001600General Information for Mars