Tune in on tuned-band IR-emitter development

-- EDN, 2/17/2000

Ion Optics, in collaboration with NASA's Jet Propulsion Laboratory, has demonstrated that lithographically defined surface structures on silicon can produce distinct "tuned" emission spectra directly related to the surface-feature dimensions. By measuring the emission and reflectance of several patterned silicon surfaces, Ion Optics' has determined that the peak absorbance wavelength and line width correlate with feature size and spacing, as well as surface conductivity. With greater output energy than infrared (IR) LEDs and the potential for comparable peak half-widths, Ion Optics' efforts show promise for a new class of tuned-band IR emitters. With the ability to design and manufacture low-cost, higher power tuned-band emitters at any wavelength in the 2- to 20-µm IR range, Ion Optics expects to offer nondispersive-IR gas- and chemical-sensor manufacturers improved measurement sensitivities. Applications involving air-quality monitoring, toxic- or combustible-gas detection, and combustion-emissions monitoring will soon have a path to improved performance.

Ion Optics developed the tuned-band emitter under a National Science Foundation Small Business Innovation Research grant and a National Institute of Standards and Technology Advanced Technology Program contract. The goal of these two programs is to develop a microelectromechanical-system-based IR gas and chemical "sensorchip," an accurate and reliable gas sensor that the company can manufacture at the costs that high-volume applications require. One of the key technological requirements of achieving this goal is the tuned-band emitter, because it offers an improved in-band-to-out-of-band SNR and removes the need for optical filters. Eliminating the optical filters allows Ion Optics to integrate the emitter and detector onto one chip, creating an IR-gas and -chemical sensorchip.

Ion Optics Inc, 1-781-788-8777, www.ion-optics.com.

-by Fran Granville