"Because of this access and the fact that QPAS is almost immune to acoustic interference, we have potential for extraordinary chemical sensitivity and selectivity," Wojcik said.
QPAS's small components represent a major advance over previous LPAS measurement methods. Historically, LPAS instruments were physically large, often measuring a meter or more in length. The entire arrangement was cumbersome, power-hungry and prone to interference from external sound and vibration.
In the QPAS technique, several QCLs can fit on a 3 x 3 millimeter chip. And the tuning forks are identical to the kind used in wristwatches, measuring only 4 millimeters long, 2 millimeters wide and 0.3 millimeter thick. A conceptual design for a battery-operated, prototype QPAS sensor, which includes 10 pairs of QCLs and tuning forks, would fit into a briefcase that is 12 inches long, 12 inches wide and 6 inches high ?and the entire thing would weigh less than 15 pounds. In addition, the instrument can operate unattended for long periods of time.
QPAS is currently at Technology Readiness Level "five," meaning that while the technical components exist and initial testing is complete, the system still must be converted to a prototype.