Abstract

The fast development of infrared technology makes infrared tracing, infrared guidance more and more applicable in the millitary arm systems. But when flying object fly against the sun, the background signal from sunlight will make it impossible to trace and detect, so it is necessary to reduce the influence of sunlight, CO2 in the atmosphere makes it impossible, becaues CO2 shows strong absorption to the sunlight of 4.184-4.454um region. If we can design an infrared filter, which transmits the light at the wavelength region, the flying object is much nearer to detect system than to the sun, which means the influence of sunlight can be neglected. To obtain sufficient sensitivity and high contrast ratio, such bandpass filter must have high transmittance (Tp) and very low background transmittance(Tb).

© 1995 Optical Society of America