Many of today’s advanced technologies were initially born out of a military need. A significant amount of R&D into high-energy lasers, for instance, has been driven by the desire for directed-energy weapons. And along with the high-energy laser development came a set of problems related to beam propagation-the high energy caused atmospheric distortion that reduced the beam’s effectiveness over distance. Adaptive-optics technology and the concept of deformable mirrors emerged to compensate for this distortion. Subsequently, adaptive-optics applications have broadened to include astronomy-they significantly improve the ability of ground-based telescopes to see clearly into space and have recently produced ultrasharp sunspot images (see www.laserfocusworld.com/articles/238601)-and free-space communications, as well as research in human vision. In the latter case, adaptive optics has been used to aid in imaging the retina and to characterize the eye. But whether adaptive optics can be applied routinely to correct human sight remains to be seen (see p. 85).
. . . and in detail
Our cover story this month describes one of many examples of the multiple approaches being developed to image our world in ever increasing detail. An x-ray laser planned at the Stanford Linear Accelerator (Palo Alto, CA) will eventually enable 3-D visualization of protein structures that cannot be crystallized for study using existing methods (see p. 13). In another example, this month’s Image Engineering feature highlights the challenge of using optical imaging to see characteristics so small that even diffraction-limited light can no longer resolve the details. Near-field optical microscopy is an important research tool based on the properties of optical propagation close to a surface that allows optical imaging on a nanometric scale (see p. 109). Meanwhile, two laser imaging techniques that apparently offer hope in the early identification of Alzheimer’s were described at last month’s OSA meeting and are described on page 13.