Fast response High Altitude Laser Optical Sensor (HALOS) for atmospheric water and temperature measurements

Advanced instrumentation and sensing methods are the key factor in the determination of many climate science research problems. Current sensing instrumentation is not fast enough to solve the problem of measuring temperature and water vapor properties on airborne platforms where small spatial scale sensing is needed due to turbulent fluctuations in the atmosphere. The opportunity exploited in this Phase I STTR proposal is that a laser-based diagnostic system for atmospheric temperature and water concentration measurements developed around a fast speed digital signal processor is capable of providing fast and accurate measurements needed for airborne platforms. Our innovation is HALOS – High Altitude Laser Optical Sensor which will perform high-speed assessment of water concentration in the Troposphere via an Aircraft mounted platform. HALOS will implement a new and unique mid-infrared (MIR) quantum cascade laser (QCL) of the distributed feedback variety (DFB) powered by a 100 kHz rep rate ramp modulated current profile which enables spectral profiling. Laser emissions will be directed into an open cavity white cell before the attenuated beam is collected on a Mercury Cadmium Telluride (MCT) photodiode. HALOS will afford probing a large span of water vapor’s 6.3 µm absorption feature without the need for moving parts. The laser and other components of HALOS will be driven by a multicore (8x C66x + 4x ARM A15 cores) digital signal processor (DSP) (Texas Instruments 66AK2H14) operating at 1.4GHz. The DSP will enable realtime processing of spectral data, and signal enhancement routines while also providing data output via a standard bus and logging to HALOS’ onboard removeable memory card. HALOS features high data output rates in the kHz range and offers spatial resolution on the order of 25 cm. Public benefits include high accuracy, real time data for weather forecasting systems. Future applications include indoor air quality monitoring for the semiconductor fabrication industry.