NASA - National Aeronautics and Space Administration

By: Sheri Beam

As NASA studies the atmosphere surrounding our planet, its researchers are working to improve the tools they use to take more accurate measurements and collect better data.

Engineers at NASA's Langley Research Center who develop laser instruments for atmospheric studies are trying to improve one of them. It's a High Spectral Resolution Lidar (HSRL) used for measuring cloud and aerosol properties that are relevant to climate research, air quality studies and satellite validation.

"The HSRL acquires measurements from the Langley B-200 aircraft and has flown to a variety of locations, including the Caribbean Islands, Mexico, Alaska and Canada," said Chris Hostetler, Langley principal investigator. "The airborne HSRL has been used extensively to validate the measurements made by NASA's (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) CALIPSO satellite-based lidar and is an early prototype for the next-generation space-borne lidar to be flown on the (Advanced Composition Explorer) mission."

The High Spectral Resolution Lidar was developed through a NASA Langley partnershipwith AdvR Inc., a Bozeman, Mont., firm that developed an optical waveguide circuit. Credit: NASA

Through the Small Business Innovation Research (SBIR) program at Langley, the engineers partnered with AdvR Inc., of Bozeman, Mont., to develop compact, lightweight, electro-optic components for lidar-based remote sensing instruments.

AdvR recently developed an optical waveguide circuit that integrates several key functions into a rugged, compact module for the laser transmitter in Langley's HSRL. A waveguide is a physical structure that guides electromagnetic waves in the optical spectrum. The AdvR module has been successfully integrated into a next generation seed laser system, which provides the precise wavelength stability required for HSRL measurements.

According to Anthony Cook, HSRL lead engineer, "the AdvR technology is unique in that it combines two optical functions in one compact, robust chip that precisely locks the laser to the required wavelength. Precise locking of the laser and filter wavelengths is critical to the accuracy of the geophysical products that we derive from the acquired data."

HRSL personnel are using the AdvR technology in lab tests to verify full-system operation. The first official flight operation of one of the AdvR-developed systems will be this year on the B-200.

Although the primary customer for this technology is Langley’s HSRL, it has other potential applications for NASA, as well as for the commercial marketplace. Some of the NASA-related applications are in NASA's other lidar remote sensing programs, such as in altimetry and Differential Absorption (DIAL) lidar at NASA’s Goddard Space Flight Center, where compact, low cost, stabilized single-frequency lasers are required.

One of the commercial applications of this technology has been for the development of lasers used in the bioscience field. AdvR partnered with PicoQuant of Berlin, a leader in the field of diode lasers and fluorescence systems, to develop a new laser source that uses a component of the original SBIR concept as a module for the laser.

"The SBIR programs have been very beneficial to this technology development, as it was through these programs that the initial fusion of our waveguide technology with opto-electronic packaging was developed," according to Shirley McNeil, senior laser systems engineer at AdvR.

The commercially available PicoQuant laser is used for a variety of applications, such as time-resolved fluorescence spectroscopy and microscopy, powerful techniques used by medical and bioscience researchers for conducting time-correlated studies at molecular levels to more fully characterize different processes in the body.

McNeil also sees other applications for AdvR SBIR-developed technology: "There are additional commercial applications, such as for the RGB display and telecom markets, and we are actively seeking industrial partners to utilize our component level products."

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NASA Langley Research Center
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