School Notes: School of Engineering & Applied Science
January/February 2015

Using photons to ‘see without looking’

For extremely photosensitive materials, even using an electron microscope to detect the material’s presence can be enough to change the material’s properties. But associate professor of electrical engineering, physics, and applied physics Hong Tang’s lab can still sense those materials, thanks to a light photon’s unique ability to act like both a wave and a particle. This wave-particle duality recognizes that quantum particles can be measured as occupying a definable space (like a particle) but paradoxically exhibit continuous wave-like movement as they move along distinct paths from one location to the next. However, if an object is placed on one of those paths, the quantum particles choose a different path, thereby sensing and avoiding the object without interacting with it. Tang’s chip-scale device recognizes when a path is being avoided, thereby sensing the presence of an object without any interaction, an ability known as “interaction-free measurement.” While other researchers have previously accomplished interaction-free measurement using traditional bulk optics, Tang’s device is the first to do so on an integrated chip, a scale that has the potential to provide significantly improved communication security as well as exponential speed-up in computational power for addressing certain problems.

Institute of Medicine elects scientist

Mark Saltzman, the Goizueta Foundation Professor and chair of biomedical engineering, has been elected to the Institute of Medicine (IOM) of the National Academies, one of the highest honors in the fields of medicine and health. With research motivated by the desire to create safer and more effective medical and surgical therapy, Saltzman has pioneered advances in drug delivery, biomaterials, nanobiotechnology, and tissue engineering—advances that have resulted in more effective use of chemotherapy, accelerated wound repair, and drug delivery to the brain. His recent patented work uses polymeric nanoparticles to deliver donor DNA molecules that can induce gene expression in targeted cells; Saltzman’s delivery method significantly increases the likelihood of DNA uptake and expression. In addition to his work in the lab, Saltzman is the founding chair of Yale’s Department of Biomedical Engineering and sole author of the textbooks Biomedical Engineering, Tissue Engineering, and Drug Delivery.