|PROPOSAL NUMBER:||03- II A2.06-9450|
|SUBTOPIC TITLE:||Modeling and Control of Complex Flows Over Aerospace Vehicles and Propulsion Systems|
|PROPOSAL TITLE:||Terahertz Quantum Cascade Laser-Based Sensors for Hypersonic Flows (7275-020)|
PRINCIPAL INVESTIGATOR/PROJECT MANAGER
(Name, E-mail, Mail Address, City/State/Zip, Phone)
Joel M Hensley
20 New England Business Center
Andover, MA 01810-1077
U.S. Citizen or Legal Resident: Yes
TECHNICAL ABSTRACT (LIMIT 200 WORDS)
Physical Sciences Inc. (PSI) proposes to design, build, test, and deliver to NASA a THz wavelength absorption sensor for continuous monitoring of atomic oxygen concentration in hypersonic flowfields. In a successful Phase I effort, PSI developed a THz wavelength Quantum Cascade Laser (QCL) at 63.2 microns, corresponding to a strong fine-structure transition of atomic oxygen. Using an external cavity design, we showed that the laser wavelength could be coarsely tuned to the atomic oxygen transition. Rapid and repeatable injection current tuning at this wavelength was also demonstrated. In the proposed Phase II program, the external cavity QCL design will be refined to include a wider continuous tuning range, higher laser operating temperature, and improved output power. The laser operation will be automated and integrated into a computer-controlled atomic oxygen sensor, providing continuous, real-time measurements of atomic oxygen concentration with a sensitivity of 10^13 atoms per cubic centimeter in a 10 Hz bandwidth. PSI will deliver, install, and test the sensor at the NASA Ames Aerodynamic Heating Facility, an arc-jet heated high-enthalpy flow facility.
POTENTIAL NASA COMMERCIAL APPLICATIONS (LIMIT 100 WORDS)
Compact, tunable terahertz lasers will be useful for container-penetrating detection of dangerous substances for homeland defense applications, detecting contraband substances for law enforcement applications, and detecting trace amounts of moisture for industrial process control.
POTENTIAL NON-NASA COMMERCIAL APPLICATIONS (LIMIT 100 WORDS)
The laser-based diagnostic developed during this project will increase the accuracy of test results at hypersonic wind tunnel facilities used to simulate atmospheric re-entry. Using these test results, NASA will be able to optimize the amount of thermal protection material used in the Space Shuttle and other vehicles, so that safety can be ensured without unnecessarily reducing the payload. The diagnostic will also provide more accurate results in facilities which simulate combustion at hypersonic speeds, thus facilitating the design of engines for future hypersonic aircraft.