ACTIVE THIN FILMS™: THE FIRST TUNABLE THIN FILMSAegis was founded on the principle of combining semiconductor thin films with optical interference coatings to provide a new class of low-cost, compact optical semiconductor devices. Through the well-known physical properties of semiconductor thin films, most significantly a refractive index which is highly dependent on temperature, the company has added entirely new functions to optical thin films. Aegis refers to this development as Active Thin Films. A typical chip consists of a transparent substrate, integrated resistive heating layer and dielectric mirrors sandwiched around a thermo-optic tunable semiconductor layer. The wavelength of light which is transmitted through the filter is a function of the temperature of the semiconductor layer. All other wavelengths are reflected. The transmitted wavelength can be changed by adjusting the current in the resistive heating layer, thus making a tunable filter. The company has filed more than 30 patents on the Active Thin Films platform and its applications. |