The latest winners of the Lemelson-MIT Rensselaer Student Prize have been named, with prizes going to students using terahertz technology at Rensselaer Polytechnic Institute (RPI) and California Institute of Technology (Caltech). Benjamin Clough, a doctoral student, won the RPI award for developing a novel method for extending the distance from which terahertz sensors can remotely detect hidden explosives, chemicals and other dangerous materials. He demonstrated a promising, cost-effective technique that employs sound waves to boost the effective distance of terahertz spectroscopy from a few feet to several meters. For this innovation, he won $30,000. Benjamin Clough won the $30,000 Lemelson-MIT Rensselaer Student Prize for developing a novel method for extending the distance from which powerful terahertz technology can remotely detect hidden explosives, chemicals and other dangerous materials. (Photo: Rensselaer/Kris Qua) "We live in an age of continuous innovation, where technologies come together in unexpected and serendipitous ways,” said Shirley Jackson, the president of RPI. “This mash-up culture, where data and applications constantly are being combined to bring value in ways that exercise the imagination, is where many stellar Rensselaer student researchers find their inspiration,” she added, citing Clough as a prime example. The Rensselaer Center for Terahertz Research is one of the most active groups worldwide in focusing on terahertz wave technology for security and defense applications. Sensors using terahertz waves can penetrate packaging materials or clothing, and can identify the unique terahertz "fingerprints" of many hidden materials. A key practical limitation of terahertz technology, however, is that it works only over short distances. Naturally occurring moisture in air absorbs terahertz waves, weakening the signal and reducing sensing capabilities. This distance limitation is not ideal for applications in bomb or hazardous materials detection, where the human operator wants to be as far away as possible from the potential threat. Clough's solution to this problem is to use sound waves to remotely "listen" to terahertz signals from a distance. Focusing two laser beams into air creates small bursts of plasma, which in turn create terahertz pulses. Another pair of lasers aimed near the target of interest creates a second plasma for detecting the terahertz pulses after they have interacted with the material. This “detection plasma” produces acoustic waves as it ionizes the air. Clough discovered that by using a sensitive microphone to "listen" to the plasma, he could detect terahertz wave information embedded in these sound waves. This audio information can then be converted into digital data and instantly checked against a library of known terahertz fingerprints, to determine the chemical composition of the mystery material. So far, Clough has successfully demonstrated the ability to use acoustics to identify the terahertz fingerprints from several meters away. He has separately demonstrated plasma acoustic detection from 11 m, limited only by available lab space. Along with the increased distance from the potentially hazardous material, an additional advantage is that his system does not require a direct line of sight to collect signals, as the microphone can still capture the audio information. Potential applications of Clough's invention include environmental monitoring of atmospheric conditions, monitoring smokestack emissions, inspecting suspicious packages or even detecting land mines – all from a safe distance. Clough is the fifth recipient of the Lemelson-MIT Rensselaer Student Prize. First given in 2007, the prize is awarded annually to an RPI senior or graduate student who has created or improved a product or process, applied a technology in a new way, redesigned a system, or demonstrated remarkable inventiveness in other ways. In California, graduate student Zheng Guoan became the recipient of the 2011 Lemelson-MIT Caltech Student Prize, also winning $30,000. He was recognized for his development of a simple, cost-effective, high-resolution on-chip microscope called a subpixel-resolving optofluidic microscope (SROFM). The technology is suitable for biological research and enables more affordable clinical and field diagnostics, which may lead to improved diagnostics for malaria and other blood-borne diseases in the developing world. In January, Zheng and two other finalists presented their inventions to a judging panel and the Caltech community. In his presentation, Zheng demonstrated his strong interest in the integration of CMOS technology with image processing, computer vision, microfluidics and nanotechnology for the design of next-generation, low-cost biomedical imaging and sensing devices. Lemelson-MIT Caltech Student Prize winner Guoan Zheng demonstrates his subpixel- resolving optofluidic microscope. (Photo: Vicki Chiu/EAS Communications Office) The other winners of the annual Lemelson-MIT Collegiate Student Prize were Scott Daigle of the University of Illinois Urbana-Champaign, who developed a system that utilizes automatic gear shifting to reduce the efforts exerted by wheelchair operators, and Alice A. Chen, an MIT graduate who developed an assortment of innovations with promising drug development implications, including a humanized mouse with a tissue-engineered human liver. "The Lemelson-MIT Collegiate Student Prize winners have shown their potential to invent broadly and bring new innovations into the world," said Joshua Schuler, executive director of the Lemelson-MIT Program. "These inventive achievements, and the students' creativity, persistence and overall collaboration, must be celebrated at the collegiate level." For more information, visit: www.eng.rpi.edu/lemelson and www.lemelson-prize.caltech.edu