At about three times the diameter of a human hair, the micromechanical optical switches that Lih Lin designed for AT&T in 1997 and 1998 were scarcely visible. And that miniscule machines she subsequently built solved a fundamental problem in telecommunications. Information travels at high speed over the optical fibers that form the backbones of telecom networks, but converting the optical signals to electronic bits for processing by traditional circuitry limits the network’s overall transmission rate and increases its cost. Lin introduced pivoting micromirrors that can switch light-wave signals directly, circumventing the pitfalls of electronic manipulation. Her technique has since been widely developed and is enhancing the capacity and reducing the cost of the optical-fiber network, as well as enabling faster and broader-band data and video transmission over the Internet. Lin’s work has yielded 16 patents and 120 published papers. As a newly appointed associate professor of electrical engineering at the University of Washington in Seattle, she plans to apply her knowledge of photonics and micromechanics to biotechnology to devise new kinds of imaging tools that can analyze individual cells.