Willis J. Tompkins (Chair) 2420 Engineering Hall 1415 Engineering Drive Madison, WI 53706-1691

Tel: 608/262-3840 Fax: 608/262-1267 tompkins@engr.wisc.edu www.engr.wisc.edu/ece

Tiny device in eyeglasses could help keep employees awake and safe while on the job

Eye Openers

Professor John G. Webster (right) and PhD candidate Ron Leder would like to prevent accidents in the workplace by warning employees when they are at risk of falling asleep (41K JPG). With support from the Center for Human Performance and Risk Analysis, the researchers are developing a tiny device that, when attached to an ordinary pair of eyeglasses, senses eyelid movement and may be able to warn users in advance that they are at a dangerously low alertness level. (Whether this advance warning can come from eyelid activity is the subject of Leder's doctoral work.) The device uses a light-emitting diode to send an infrared beam toward the eye, and a nearby photodiode that measures light reflected from the eye. (Open eyes reflect less light than closed eyes.) While there are other alertness sensors on the market, they must either be attached to the eyelid or they don't measure complete motion of the eyelid, says Webster. The researchers' goal is to develop a product that is predictive. "We'd like something that says `the probability is X percent that in the next 10 minutes you are going to have an alertness outage," says Leder.

New faculty member's laser work to assist in cancer treatment, data storage, printing

Assistant Professor Luke J. Mawst, a recent addition to the ECE faculty, has been working with Applied Optronics Corp. of New Jersey to develop a high-output aluminum-free diode laser with a wavelength of 730nm. "These devices would for the first time allow reliable operation at this wavelength," explains Mawst. The lasers would have various medical applications, including photodynamic therapy for cancer treatment. They would also benefit such industries as optical data storage and high-speed, high-resolution printing. Mawst's recent efforts have focused on an aluminum-free material system (InGaAsP/InGaP/GaAs), which he says is easy to fabricate and highly reliable. "However, realizing the full potential of this system requires an understanding of the nature of quantum-well growth for aluminum-free materials, and the influence on device performance," says Mawst. "Understanding the influence of the material properties on device characteristics can lead to significant improvements in performance." Mawst is also interested in the metalorganic chemical vapor deposition (MOCVD) growth process, which allows for the controlled growth of ultra-thin semiconductor films with abrupt interfaces. This process enables the fabrication of high-performance quantum-well lasers and other optoelectronic devices.

Optimal power system goal of new center

To help develop the most competitive, efficient, responsive and environmentally responsible "next generation" electric-power system, the industry-university cooperative program of the National Science Foundation has established the Power Systems Engineering Research Center (PSerc), with UW-Madison as one of the initial four participating universities. "To be competitive, future power systems must have the ability to quickly reconfigure network flows in response to technical and economic pressures," explains ECE Professor Robert H. Lasseter, UW-Madison's PSerc site director. "This requirement means that the full capacity of every line in the system must be available at any and every instant in order to realize a substantial economic benefit." In order to achieve this high performance level, he adds, innovative applications of emerging concepts in communications, computing, and power electronics will be required. Innovations in this field will also require the expertise of nontraditional power-system engineers and scientists. PSerc's vision includes educating a new breed of power engineer to ensure that talented people are trained to design and manage the new systems. Other college faculty involved with PSerc include Associate Professor Ian Dobson, and Professors Christopher L. DeMarco and Fernando L. Alvarado.

Laser technology leaps forward

Solid-state diode-pumped lasers, such as ND-YAG, are widely used for materials processing, medical therapy, and, in the case of Lawrence Livermore National Laboratory, inertial confinement fusion. Philip D. Reed Professor Dan Botez is receiving funding from this national laboratory, as well as laser manufacturer Coherent, Inc., to develop improved diode-pumped lasers at a wavelength of 0.81 micrometers. However, rather than using the traditional aluminum-gallium-arsenide (AlGaAs) compound that tends to produce unreliable products, Botez is using an aluminum-free compound grown via metalorganic chemical vapor deposition. His research has resulted in world-record power performances (e.g., 6.1W CW from 100um-aperture devices) as well as diode-damage power levels at least twice as high as those for the conventional AlGaAs-based lasers. "We have demonstrated the potential for making diodes at least twice as reliable or which will operate at twice the power of the diode pumps currently available commercially," says Botez.