NASA SBIR 2004 Solicitation


PROPOSAL NUMBER: 04 E1.06-9371
SUBTOPIC TITLE: Passive Infrared - Submillimeter
PROPOSAL TITLE: Quantum Cascade Laser-Based Local Oscillator for Terahertz Astronomy (7275-070)

SMALL BUSINESS CONCERN (Name, E-mail, Mail Address, City/State/Zip, Phone)
Physical Sciences Inc
20 New England Business Ctr
Andover, MA 01810-1077

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Joel M. Hensley
20 New England Business Ctr
Andover, MA 01810-1077

Scientists at JPL measure radiation emitted in the far-infrared (or terahertz) region of the spectrum to study the history of the universe and the Earth's atmosphere. The most commonly used detection technique is frequency mixing between that emission and a local oscillator operating at a frequency close to the emission line. The local oscillators available today, such as optically pumped terahertz lasers or frequency-multiplied millimeter-wave sources, suffer from a number of shortcomings including limited tuning range, inadequate wavelength coverage, large size, and low wallplug efficiency. Physical Sciences Inc. has recently demonstrated a novel, tunable THz laser source based on an external cavity stabilized THz Quantum Cascade Laser with discontinuous tuning over a 30 GHz band at 147 wavenumbers. In the proposed Phase I program, we will use an available 158 wavenumber THz QCL to optimize the external cavity design for continuous, mode-hop free tuning over an expected range of 100 GHz with a target laser linewidth below 1 MHz. Such a laser has never been previously demonstrated. During Phase II we will prove practicality by optimizing the properties of the laser, packaging it into a form suitable for terahertz emission experiments, and delivering it to JPL.

By using the laser source developed under this project as a local oscillator, JPL scientists will be able to measure terahertz emission from at least one new target species of importance to astronomy or atmospheric science. Future versions of this laser source will be tailored to match other target species, until the entire terahertz region of the spectrum has been covered. As a result, the JPL scientists will develop a better understanding of the evolution of the universe. In addition, they will learn more about problems with Earth's atmosphere, including global warming, ozone destruction, and pollution.

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.