Techniques to "see" through opaque media have been the subject of much research and development. Doctors have long used x-rays to create pictures of the skeletal system, but x-rays are not an ideal light source. Their short wavelengths can cause harm and cannot solve all the questions of medical diagnostic imaging. Nor can they meet all the challenges posed by the broad field of nondestructive testing, which has widespread applications across a variety of industries.
In recent years, scientists have successfully applied laser and electro-optic technologies to this type of imaging problem. Conventional imaging—that is, the technique that captures pictures of nonmicroscopic objects in room light—is enjoying a huge growth in applications as clever engineers put together better systems with faster cameras and faster computers. For the creation of images of microscopic entities beyond the capabilities of light microscopes, however, the technological answers are not as straightforward. One approach adopted by several research groups is chemical imaging.
This technique goes beyond the microscopic image and creates images based on chemical information. For example, the images on the cover, which are discussed in the article on p. 75 by Patrick J. Treado, were obtained by identifying an area of biopsied human breast tissue through a microscope and using Raman spectroscopy to scan a particular wavelength region to identify aggregate structures that proved to be Dacron polyester. Other experiments described in Treado's article include monitoring of coatings on automotive parts, an interesting application of nondestructive testing. In addition to using Raman spectroscopy to obtain chemical information, the technique can be combined with Fourier-transform infrared spectroscopy. These two spectroscopic techniques can identify almost any chemical through its characteristic fingerprint spectrum.
Software options continue to proliferate
This issue contains our second annual "Software Handbook" (following p. 160), for which associate editors Rick DeMeis and Kristin Lewotsky identified areas in which software is extending applications. The articles look at new ways to visualize large amounts of data, expand bandwidth capabilities of existing instruments, keep track of iterations in optical design, and perform high-speed data acquisition.